Image rotation in an endoscopic fluorescence imaging system

ABSTRACT

Image rotation in an endoscopic fluorescence imaging system is described. A system includes an emitter for emitting pulses of electromagnetic radiation and an image sensor comprising a pixel array for sensing reflected electromagnetic radiation. The system includes a rotation sensor for detecting an angle of rotation of a lumen relative to a handpiece of an endoscope. The system is such that at least a portion of the pulses of electromagnetic radiation emitted by the emitter comprises electromagnetic radiation having a wavelength from about 770 nm to about 790 nm and/or from about 795 nm to about 815 nm.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 62/864,245, filed Jun. 20, 2019, titled “IMAGE ROTATIONUSING SOFTWARE FOR HYPERSPECTRAL AND FLUORESCENCE IMAGING,” which isincorporated herein by reference in its entirety, including but notlimited to those portions that specifically appear hereinafter, theincorporation by reference being made with the following exception: Inthe event that any portion of the above-referenced provisionalapplication is inconsistent with this application, this applicationsupersedes the above-referenced provisional application.

TECHNICAL FIELD

This disclosure is directed to digital imaging and is particularlydirected to fluorescence imaging in a light deficient environment.

BACKGROUND

Advances in technology have provided advances in imaging capabilitiesfor medical use. An endoscope may be used to look inside a body andexamine the interior of an organ or cavity of the body. Endoscopes areused for investigating a patient's symptoms, confirming a diagnosis, orproviding medical treatment. A medical endoscope may be used for viewinga variety of body systems and parts such as the gastrointestinal tract,the respiratory tract, the urinary tract, the abdominal cavity, and soforth. Endoscopes may further be used for surgical procedures such asplastic surgery procedures, procedures performed on joints or bones,procedures performed on the neurological system, procedures performedwithin the abdominal cavity, and so forth.

In some instances of endoscopic imaging, it may be beneficial ornecessary to view a space in color. A digital color image includes atleast three layers, or “color channels,” that cumulatively form an imagewith a range of hues. Each of the color channels measures the intensityand chrominance of light for a spectral band. Commonly, a digital colorimage includes a color channel for red, green, and blue spectral bandsof light (this may be referred to as a Red Green Blue or RGB image).Each of the red, green, and blue color channels include brightnessinformation for the red, green, or blue spectral band of light. Thebrightness information for the separate red, green, and blue layers arecombined to create the color image. Because a color image is made up ofseparate layers, a conventional digital camera image sensor includes acolor filter array that permits red, green, and blue visible lightwavelengths to hit selected pixel sensors. Each individual pixel sensorelement is made sensitive to red, green, or blue wavelengths and willonly return image data for that wavelength. The image data from thetotal array of pixel sensors is combined to generate the RGB image. Theat least three distinct types of pixel sensors consume significantphysical space such that the complete pixel array cannot fit in thesmall distal end of an endoscope.

Because a traditional image sensor cannot fit in the distal end of anendoscope, the image sensor is traditionally located in a handpiece unitof an endoscope that is held by an endoscope operator and is not placedwithin the body cavity. In such an endoscope, light is transmitted alongthe length of the endoscope from the handpiece unit to the distal end ofthe endoscope. This configuration has significant limitations.Endoscopes with this configuration are delicate and can be easilymisaligned or damaged when bumped or impacted during regular use. Thiscan significantly degrade the quality of the images and necessitate thatthe endoscope be frequently repaired or replaced.

The traditional endoscope with the image sensor placed in the handpieceunit is further limited to capturing only color images. However, in someimplementations, it may be desirable to capture images with fluorescenceimage data in addition to color image data. Fluorescence is the emissionof light by a substance that has absorbed light or other electromagneticradiation. Certain fluorescent materials “glow” or emit a distinct colorthat is visible to the human eye when the fluorescent material issubjected to ultraviolet light or other wavelengths of electromagneticradiation. Certain fluorescent materials will cease to glow nearlyimmediately when the radiation source stops.

Fluorescence occurs when an orbital electron of a molecule, atom, ornanostructure is excited by light or other electromagnetic radiation,and then relaxes to its ground state by emitting a photon from theexcited state. The specific frequencies of electromagnetic radiationthat excite the orbital electron, or are emitted by the photon duringrelaxation, are dependent on the atom, molecule, or nanostructure.Fluorescence imaging has numerous practical applications, includingmineralogy, gemology, medicine, spectroscopy for chemical sensors,detecting biological processes or signals, and others. Fluorescence canbe used in biochemistry and medicine as a non-destructive means fortracking or analyzing biological molecules. Some fluorescent reagents ordyes can be configured to attach to certain types of tissue and therebydraw attention to that type of tissue.

However, fluorescence imaging requires specialized emissions ofelectromagnetic radiation and specialized imaging sensors capable ofreading the specific relaxation wavelength for a specific fluorescentreagent. Different reagents or dyes are sensitive to differentwavelengths of electromagnetic radiation and emit different wavelengthsof electromagnetic radiation when fluoresced. A fluorescent imagingsystem may be highly specialized and tuned for a certain reagent or dye.Such imaging systems are useful for limited applications and are notcapable of fluorescing more than one reagent or structure during asingle imaging session. It is very costly to use multiple distinctimaging systems that are each configured for fluorescing a differentreagent. Additionally, it may be desirable to administer multiplefluorescent reagents in a single imaging session and view the multiplereagents in a single overlaid image.

In light of the foregoing, described herein are systems, methods, anddevices for fluorescent imaging in a light deficient environment. Suchsystems, methods, and devices may provide multiple datasets foridentifying critical structures in a body and providing precise andvaluable information about the body cavity.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive implementations of the disclosure aredescribed with reference to the following figures, wherein likereference numerals refer to like parts throughout the various viewsunless otherwise specified. Advantages of the disclosure will becomebetter understood with regard to the following description andaccompanying drawings where:

FIG. 1 is a schematic view of a system for digital imaging in a lightdeficient environment with a paired emitter and pixel array;

FIG. 2 is a system for providing illumination to a light deficientenvironment for endoscopic imaging;

FIG. 2A is a schematic diagram of complementary system hardware;

FIGS. 3A to 3D are illustrations of the operational cycles of a sensorused to construct an exposure frame;

FIG. 4A is a graphical representation of the operation of an embodimentof an electromagnetic emitter;

FIG. 4B is a graphical representation of varying the duration andmagnitude of the emitted electromagnetic pulse to provide exposurecontrol;

FIG. 5 is a graphical representation of an embodiment of the disclosurecombining the operational cycles of a sensor, the electromagneticemitter, and the emitted electromagnetic pulses of FIGS. 3A-4B, whichdemonstrate the imaging system during operation;

FIG. 6A is a schematic diagram of a process for recording a video withfull spectrum light over a period of time from t(0) to t(1);

FIG. 6B is a schematic diagram of a process for recording a video bypulsing portioned spectrum light over a period of time from t(0) tot(1);

FIGS. 7A-7E illustrate schematic views of the processes over an intervalof time for recording a frame of video for both full spectrum light andpartitioned spectrum light;

FIG. 8 illustrates an endoscopic imaging system including a handpieceand an endoscope tube, wherein the handpiece and the endoscope tube orrotatable with respect to one another;

FIG. 9 illustrates an embodiment of a rotation sensor for implementationwithin an endoscopic imaging system;

FIG. 10 illustrates an embodiment of a rotation sensor forimplementation within an endoscopic imaging system;

FIG. 11 illustrates an embodiment of a rotation sensor forimplementation within an endoscopic imaging system;

FIGS. 12A and 12B illustrate implementations of an endoscopic imagingsystem including an outer lumen, a distal lens, a prism, and an imagesensor for enabling a wide-angle field of vision for digital imaging;

FIGS. 13A-13C illustrate a light source having a plurality of emitters;

FIG. 14 illustrates a single optical fiber outputting via a diffuser atan output to illuminate a scene in a light deficient environment;

FIG. 15 illustrates a portion of the electromagnetic spectrum dividedinto a plurality of different sub-spectrums which may be emitted byemitters of a light source in accordance with the principles andteachings of the disclosure;

FIG. 16 is a schematic diagram illustrating a timing sequence foremission and readout for generating an image frame comprising aplurality of exposure frames resulting from differing partitions ofpulsed light;

FIG. 17 illustrates an imaging system including a single cut filter forfiltering wavelengths of electromagnetic radiation;

FIG. 18 illustrates an imaging system comprising a multiple cut filterfor filtering wavelengths of electromagnetic radiation;

FIGS. 19A and 19B illustrate a perspective view and a side view,respectively, of an implementation of an imaging sensor having aplurality of pixel arrays for producing a three-dimensional image,wherein the plurality of pixel arrays and the image sensor are built ona plurality of substrates;

FIGS. 20A and 20B illustrate an implementation having a plurality ofpixel arrays for producing a three-dimensional image in accordance withthe principles and teachings of the disclosure; and

FIGS. 21A and 21B illustrate a perspective view and a side view,respectively, of an implementation of an imaging sensor built on aplurality of substrates, wherein a plurality of pixel columns formingthe pixel array are located on the first substrate and a plurality ofcircuit columns are located on a second substrate and showing anelectrical connection and communication between one column of pixels toits associated or corresponding column of circuitry.

DETAILED DESCRIPTION

Disclosed herein are systems, methods, and devices for digital imagingthat may be primarily suited to medical applications such as medicalendoscopic imaging. An embodiment of the disclosure is an endoscopicsystem for fluorescence and color imaging in a light deficientenvironment. Such methods, systems, and computer-based productsdisclosed herein provide imaging or diagnostic capabilities for use inmedical robotics applications, such as the use of robotics forperforming imaging procedures, surgical procedures, and the like.

An embodiment of the disclosure is an endoscopic imaging system with theimage sensor disposed in a distal tip of the endoscope. Thisconfiguration enables numerous advantages over conventional endoscopesas discussed herein. However, this configuration also introduces thechallenge of establishing correct image orientation for a user. In someinstances, and depending on preferences of the user, the imageorientation should reflect the orientation of a handpiece unit of theendoscope with respect to the scene being imaged. In an embodiment,correct image orientation is established and maintained throughpost-processing in the image signal processing (ISP) pipeline. In thisembodiment, a digital representation of the angle of the endoscope withrespect to the handpiece unit is continuously available to and adjustedby the ISP during operation.

Conventional endoscopes are designed such that the image sensor isplaced at a proximal end of the device within a handpiece unit. Thisconfiguration requires that incident light travel the length of theendoscope by way of precisely coupled optical elements. The preciseoptical elements can easily be misaligned during regular use, and thiscan lead to image distortion or image loss. Embodiments of thedisclosure place an image sensor within the highly space-constrainedenvironment in the distal end of the endoscope itself. This providesgreater optical simplicity when compared with implementations known inthe art. However, an acceptable solution to this approach is by no meanstrivial and introduces its own set of engineering challenges.

There can be a noticeable loss to image quality when the overall size ofan image sensor is minimized such that the image sensor can fit withinthe distal tip of an endoscope. The area of the pixel array of the imagesensor can be reduced by reducing the number of pixels and/or thesensing area of each individual pixel. Each of these modificationsimpacts the resolution, sensitivity, and dynamic range of the resultantimages. Traditional endoscopic imaging systems are geared toward sensingsteady broadband illumination and providing color information by virtueof segmented pixel arrays such as the Bayer pattern array. In light ofthe deficiencies associated with segmented pixel arrays, disclosedherein are alternative systems and methods that use a monochromatic (maybe referred to as “color agnostic”) pixel array that does not includeindividual pixel filters. In the embodiments disclosed herein, the colorinformation is provided by pulsing an emitter with different wavelengthsof electromagnetic radiation. The pulsed imaging system disclosed hereincan generate color images with fluorescence imaging data overlaidthereon.

In an embodiment, the color information is determined by capturingindependent exposure frames in response to pulses of differentwavelengths of electromagnetic radiation. The alternative pulses mayinclude red, green, and blue wavelengths for generating an RGB imageframe consisting of a red exposure frame, a green exposure frame, and ablue exposure frame. In an alternative implementation, the alternativepulses may include luminance (“Y”), red chrominance (“Cr”), and bluechrominance “(Cb”) pulses of light for generating a YCbCr image frameconsisting of luminance data, red chrominance data, and blue chrominancedata. The color image frame may further include data from a fluorescenceexposure frame overlaid on the RGB or YCbCr image frame. Thefluorescence pulse may include one or more pulses of electromagneticradiation for eliciting a spectral response. In an embodiment, thefluorescence emission includes one or more of electromagnetic radiationhaving a wavelength from about 770 nm to about 790; or from about 795 nmto about 815 nm. Alternating the wavelengths of the pulsedelectromagnetic radiation allows the full pixel array to be exploitedand avoids the artifacts introduced by Bayer pattern pixel arrays.

In some instances, it is desirable to generate endoscopic imaging withmultiple data types or multiple images overlaid on one another. Forexample, it may be desirable to generate a color (RGB or YCbCr) imagethat further includes fluorescence imaging data overlaid on the colorimage. An overlaid image of this nature may enable a medicalpractitioner or computer program to identify critical body structuresbased on the fluorescence imaging data. Historically, this would requirethe use of multiple sensor systems including an image sensor for colorimaging and one or more additional image sensors for fluorescenceimaging. In such systems, the multiple image sensors would have multipletypes of pixel sensors that are each sensitive to distinct ranges ofelectromagnetic radiation. In systems known in the art, this includesthe three separate types of pixel sensors for generating a color imagealong with additional pixel sensors for generating the fluorescenceimage data at different wavelengths of the electromagnetic spectrum.These multiple different pixel sensors consume a prohibitively largephysical space and cannot be located at a distal tip of the endoscope.In systems known in the art, the camera or cameras are not placed at thedistal tip of the endoscope and are instead placed in an endoscopehandpiece or robotic unit. This introduces numerous disadvantages andcauses the endoscope to be very delicate. The delicate endoscope may bedamaged and image quality may be degraded when the endoscope is bumpedor impacted during use. Considering the foregoing, disclosed herein aresystems, methods, and devices for endoscopic imaging in a lightdeficient environment. The systems, methods, and devices disclosedherein provide means for employing multiple imaging techniques in asingle imaging session while permitting one or more image sensors to bedisposed in a distal tip of the endoscope.

Fluorescence Imaging

The systems, methods, and devices disclosed herein provide means forgenerating fluorescence imaging data in a light deficient environment.The fluorescence imaging data may be used to identify certain materials,tissues, components, or processes within a body cavity or other lightdeficient environment. In certain embodiments, fluorescence imaging isprovided to a medical practitioner or computer-implemented program toenable the identification of certain structures or tissues within abody. Such fluorescence imaging data may be overlaid on black-and-whiteor RGB images to provide additional information and context.

Fluorescence is the emission of light by a substance that has absorbedlight or other electromagnetic radiation. Certain fluorescent materialsmay “glow” or emit a distinct color that is visible to the human eyewhen the fluorescent material is subjected to ultraviolet light or otherwavelengths of electromagnetic radiation. Certain fluorescent materialswill cease to glow nearly immediately when the radiation source stops.

Fluorescence occurs when an orbital electron of a molecule, atom, ornanostructure is excited by light or other electromagnetic radiation,and then relaxes to its ground state by emitting a photon from theexcited state. The specific frequencies of electromagnetic radiationthat excite the orbital electron, or are emitted by the photon duringrelaxation, are dependent on the particular atom, molecule, ornanostructure. In most cases, the light emitted by the substance has alonger wavelength, and therefore lower energy, than the radiation thatwas absorbed by the substance. However, when the absorbedelectromagnetic radiation is intense, it is possible for one electron toabsorb two photons. This two-photon absorption can lead to emission ofradiation having a shorter wavelength, and therefore higher energy, thanthe absorbed radiation. Additionally, the emitted radiation may also bethe same wavelength as the absorbed radiation.

Fluorescence imaging has numerous practical applications, includingmineralogy, gemology, medicine, spectroscopy for chemical sensors,detecting biological processes or signals, and so forth. Fluorescencemay particularly be used in biochemistry and medicine as anon-destructive means for tracking or analyzing biological molecules.The biological molecules, including certain tissues or structures, maybe tracked by analyzing the fluorescent emission of the biologicalmolecules after being excited by a certain wavelength of electromagneticradiation. However, relatively few cellular components are naturallyfluorescent. In certain implementations, it may be desirable tovisualize a certain tissue, structure, chemical process, or biologicalprocess that is not intrinsically fluorescent. In such animplementation, the body may be administered a dye or reagent that mayinclude a molecule, protein, or quantum dot having fluorescentproperties. The reagent or dye may then fluoresce after being excited bya certain wavelength of electromagnetic radiation. Different reagents ordyes may include different molecules, proteins, and/or quantum dots thatwill fluoresce at particular wavelengths of electromagnetic radiation.Thus, it may be necessary to excite the reagent or dye with aspecialized band of electromagnetic radiation to achieve fluorescenceand identify the desired tissue, structure, or process in the body.

Fluorescence imaging may provide valuable information in the medicalfield that may be used for diagnostic purposes and/or may be visualizedin real-time during a medical procedure. Specialized reagents or dyesmay be administered to a body to fluoresce certain tissues, structures,chemical processes, or biological processes. The fluorescence of thereagent or dye may highlight body structures such as blood vessels,nerves, particular organs, and so forth. Additionally, the fluorescenceof the reagent or dye may highlight conditions or diseases such ascancerous cells or cells experiencing a certain biological or chemicalprocess that may be associated with a condition or disease. Thefluorescence imaging may be used in real-time by a medical practitioneror computer program for differentiating between, for example, cancerousand non-cancerous cells during a surgical tumor extraction. Thefluorescence imaging may further be used as a non-destructive means fortracking and visualizing over time a condition in the body that wouldotherwise not be visible by the human eye or distinguishable in an RGBimage.

The systems, methods, and devices for generating fluorescence imagingdata may be used in coordination with reagents or dyes. Some reagents ordyes are known to attach to certain types of tissues and fluoresce atspecific wavelengths of the electromagnetic spectrum. In animplementation, a reagent or dye is administered to a patient that isconfigured to fluoresce when activated by certain wavelengths of light.The endoscopic imaging system disclosed herein is used to excite andfluoresce the reagent or dye. The fluorescence of the reagent or dye iscaptured by the endoscopic imaging system to aid in the identificationof tissues or structures in the body cavity. In an implementation, apatient is administered a plurality of reagents or dyes that are eachconfigured to fluoresce at different wavelengths and/or provide anindication of different structures, tissues, chemical reactions,biological processes, and so forth. In such an implementation, theendoscopic imaging system emits each of the applicable wavelengths tofluoresce each of the applicable reagents or dyes. This may negate theneed to perform individual imaging procedures for each of the pluralityof reagents or dyes.

Imaging reagents can enhance imaging capabilities in pharmaceutical,medical, biotechnology, diagnostic, and medical procedure industries.Many imaging techniques such as X-ray, computer tomography (CT),ultrasound, magnetic resonance imaging (MRI), and nuclear medicine,mainly analyze anatomy and morphology and are unable to detect changesat the molecular level. Fluorescent reagents, dyes, and probes,including quantum dot nanoparticles and fluorescent proteins, assistmedical imaging technologies by providing additional information aboutcertain tissues, structures, chemical processes, and/or biologicalprocesses that are present within the imaging region. Imaging usingfluorescent reagents enables cell tracking and/or the tracking ofcertain molecular biomarkers. Fluorescent reagents may be applied forimaging cancer, infection, inflammation, stem cell biology, and others.Numerous fluorescent reagents and dyes are being developed and appliedfor visualizing and tracking biological processes in a non-destructivemanner. Such fluorescent reagents may be excited by a certain wavelengthor band of wavelengths of electromagnetic radiation. Similarly, thosefluorescent reagents may emit relaxation energy at a certain wavelengthor band of wavelengths when fluorescing, and the emitted relaxationenergy may be read by a sensor to determine the location and/orboundaries of the reagent or dye.

In an embodiment of the disclosure, an endoscopic imaging system pulseselectromagnetic radiation for exciting an electron in a fluorescentreagent or dye. The endoscopic imaging system may pulse multipledifferent wavelengths of electromagnetic radiation for fluorescingmultiple different reagents or dyes during a single imaging session. Theendoscope includes an image sensor that is sensitive to the relaxationwavelength(s) of the one or more reagents or dyes. The imaging datagenerated by the image sensor can be used to identify a location andboundary of the one or more reagents or dyes. The endoscope system mayfurther pulse electromagnetic radiation in red, green, and blue bands ofvisible light such that the fluorescence imaging can be overlaid on anRGB video stream.

Pulsed Imaging

Some implementations of the disclosure include aspects of a combinedsensor and system design that allows for high definition imaging withreduced pixel counts in a controlled illumination environment. This isaccomplished with frame-by-frame pulsing of a single-color wavelengthand switching or alternating each frame between a single, differentcolor wavelength using a controlled light source in conjunction withhigh frame capture rates and a specially designed correspondingmonochromatic sensor. Additionally, electromagnetic radiation outsidethe visible light spectrum may be pulsed to enable the generation of afluorescence image. The pixels may be color agnostic such that eachpixel generates data for each pulse of electromagnetic radiation,including pulses for red, green, and blue visible light wavelengthsalong with other wavelengths used for fluorescence imaging.

A system of the disclosure is an endoscopic imaging system for use in alight deficient environment. The system includes an endoscope comprisingan image sensor, wherein the image sensor is configured to sensereflected electromagnetic radiation for generating a plurality ofexposure frames that can be combined to generate an RGB image frame withfluorescence data overlaid thereon. The system includes an emitter foremitting pulses of electromagnetic radiation. The system includes acontroller (may alternatively be referred to as a “control circuit” inelectronic communication with the image sensor and the emitter. Thecontroller controls a duty cycle of the emitter in response to signalscorresponding to a duty cycle of the emitter. The image sensor includesbidirectional pads that can send and receive information. Thebidirectional pads of the image sensor operate in a frame period dividedinto three defined states, including a rolling readout state, a serviceline state, and a configuration state. The system includes an oscillatordisposed in the controller and a frequency detector connected to thecontroller. The frequency detector controls a clock frequency of theimage sensor in response to signals from the controller that correspondto the frequency of the oscillator. The system is such that clock signaldata is transmitted from the bidirectional pads of the image sensor tothe controller during the service line phase and the configurationphase. The system is such that exposure frames are synchronized withoutthe use of an input clock or a data transmission clock.

For the purposes of promoting an understanding of the principles inaccordance with the disclosure, reference will now be made to theembodiments illustrated in the drawings and specific language will beused to describe the same. It will nevertheless be understood that nolimitation of the scope of the disclosure is thereby intended. Anyalterations and further modifications of the inventive featuresillustrated herein, and any additional applications of the principles ofthe disclosure as illustrated herein, which would normally occur to oneskilled in the relevant art and having possession of this disclosure,are to be considered within the scope of the disclosure claimed.

Before the structure, systems and methods for producing an image in alight deficient environment are disclosed and described, it is to beunderstood that this disclosure is not limited to the particularstructures, configurations, process steps, and materials disclosedherein as such structures, configurations, process steps, and materialsmay vary somewhat. It is also to be understood that the terminologyemployed herein is used for the purpose of describing particularembodiments only and is not intended to be limiting since the scope ofthe disclosure will be limited only by the appended claims andequivalents thereof.

In describing and claiming the subject matter of the disclosure, thefollowing terminology will be used in accordance with the definitionsset out below.

It must be noted that, as used in this specification and the appendedclaims, the singular forms “a,” “an,” and “the” include plural referentsunless the context clearly dictates otherwise.

As used herein, the terms “comprising,” “including,” “containing,”“characterized by,” and grammatical equivalents thereof are inclusive oropen-ended terms that do not exclude additional, unrecited elements ormethod steps.

As used herein, the phrase “consisting of” and grammatical equivalentsthereof exclude any element or step not specified in the claim.

As used herein, the phrase “consisting essentially of” and grammaticalequivalents thereof limit the scope of a claim to the specifiedmaterials or steps and those that do not materially affect the basic andnovel characteristic or characteristics of the claimed disclosure.

As used herein, the term “proximal” shall refer broadly to the conceptof a portion nearest an origin.

As used herein, the term “distal” shall generally refer to the oppositeof proximal, and thus to the concept of a portion farther from anorigin, or a furthest portion, depending upon the context.

As used herein, color sensors or multi spectrum sensors are thosesensors known to have a color filter array (CFA) thereon to filter theincoming electromagnetic radiation into its separate components. In thevisual range of the electromagnetic spectrum, such a CFA may be built ona Bayer pattern or modification thereon to separate green, red and bluespectrum components of the light.

As used herein, monochromatic sensor refers to an unfiltered imagingsensor. Since the pixels are color agnostic, the effective spatialresolution is appreciably higher than for their color (typicallyBayer-pattern filtered) counterparts in conventional single-sensorcameras. Monochromatic sensors may also have higher quantum efficiencybecause fewer incident photons are wasted between individual pixels.

As used herein, an emitter is a device that is capable of generating andemitting electromagnetic pulses. Various embodiments of emitters may beconfigured to emit pulses and have very specific frequencies or rangesof frequencies from within the entire electromagnetic spectrum. Pulsesmay comprise wavelengths from the visible and non-visible ranges. Anemitter may be cycled on and off to produce a pulse or may produce apulse with a shutter mechanism. An emitter may have variable poweroutput levels or may be controlled with a secondary device such as anaperture or filter. An emitter may emit broad spectrum or full spectrumelectromagnetic radiation that may produce pulses through colorfiltering or shuttering. An emitter may comprise a plurality ofelectromagnetic sources that act individually or in concert.

It should be noted that as used herein the term “light” is both aparticle and a wavelength and is intended to denote electromagneticradiation that is detectable by a pixel array 122 and may includewavelengths from the visible and non-visible spectrums ofelectromagnetic radiation. The term “partition” is used herein to mean apre-determined range of wavelengths of the electromagnetic spectrum thatis less than the entire spectrum, or in other words, wavelengths thatmake up some portion of the electromagnetic spectrum. As used herein, anemitter is a light source that may be controllable as to the portion ofthe electromagnetic spectrum that is emitted or that may operate as tothe physics of its components, the intensity of the emissions, or theduration of the emission, or all the above. An emitter may emit light inany dithered, diffused, or collimated emission and may be controlleddigitally or through analog methods or systems. As used herein, anelectromagnetic emitter is a source of a burst of electromagnetic energyand includes light sources, such as lasers, LEDs, incandescent light, orany light source that can be digitally controlled.

Referring now to the figures, FIG. 1 illustrates a schematic diagram ofa system 100 for sequential pulsed imaging in a light deficientenvironment. The system 100 can be deployed to generate an RGB imagewith fluorescence imaging data overlaid on the RGB image. The system 100includes an emitter 102 and a pixel array 122. The emitter 102 pulses apartition of electromagnetic radiation in the light deficientenvironment 112 and the pixel array 122 senses instances of reflectedelectromagnetic radiation. The emitter 102 and the pixel array 122 workin sequence such that one or more pulses of a partition ofelectromagnetic radiation results in image data sensed by the pixelarray 122.

It should be noted that as used herein the term “light” is both aparticle and a wavelength and is intended to denote electromagneticradiation that is detectable by a pixel array 122 and may includewavelengths from the visible and non-visible spectrums ofelectromagnetic radiation. The term “partition” is used herein to mean apre-determined range of wavelengths of the electromagnetic spectrum thatis less than the entire spectrum, or in other words, wavelengths thatmake up some portion of the electromagnetic spectrum. As used herein, anemitter is a light source that may be controllable as to the portion ofthe electromagnetic spectrum that is emitted or that may operate as tothe physics of its components, the intensity of the emissions, or theduration of the emission, or all the above. An emitter may emit light inany dithered, diffused, or collimated emission and may be controlleddigitally or through analog methods or systems. As used herein, anelectromagnetic emitter is a source of a burst of electromagnetic energyand includes light sources, such as lasers, LEDs, incandescent light, orany light source that can be digitally controlled.

A pixel array 122 of an image sensor may be paired with the emitter 102electronically, such that the emitter 102 and the pixel array 122 aresynced during operation for both receiving the emissions and for theadjustments made within the system. The emitter 102 may be tuned to emitelectromagnetic radiation in the form of a laser, which may be pulsed toilluminate a light deficient environment 112. The emitter 102 may pulseat an interval that corresponds to the operation and functionality ofthe pixel array 122. The emitter 102 may pulse light in a plurality ofelectromagnetic partitions such that the pixel array receiveselectromagnetic energy and produces a dataset that corresponds in timewith each specific electromagnetic partition. For example, FIG. 1illustrates an implementation wherein the emitter 102 emits fourdifferent partitions of electromagnetic radiation, including red 104,green 106, blue 108, and a fluorescence excitation 110 wavelength. Thefluorescence excitation 110 wavelength may include a plurality ofdifferent partitions of electromagnetic radiation that are selected tofluoresce a plurality of fluorescent reagents that are present withinthe light deficient environment 112. The fluorescent excitation 110wavelength may be selected to fluoresce a particular fluorescent reagentthat is present in the light deficient environment 112.

In an alternative embodiment not illustrated in FIG. 1, the pulsedemissions of light include a luminance (“Y”) emission, a red chrominance(“Cr”) emission, and a blue chrominance (“Cb”) emission in place of thepulsed red 104, pulsed green 106, and pulsed blue 108 emissions. In anembodiment, the controller or the emitter 102 modules the pulses ofelectromagnetic radiation to provide luminance and/or chrominanceinformation according to color transformation coefficients that convertlight energy from red, green, and blue light energy spaces to luminance,red chrominance, and blue chrominance light energy space. The pulsedemissions of light may further include modulated blue chrominance(“Y+Cb”) pulses and/or modulated red chrominance (“Y+Cr”) pulses.

The light deficient environment 112 includes structures, tissues, andother elements that reflect a combination of red 114, green 116, and/orblue 118 light. A structure that is perceived as being red 114 willreflect back pulsed red 104 light. The reflection off the red structureresults in sensed red 105 by the pixel array 122 following the pulsedred 104 emission. The data sensed by the pixel array 122 results in ared exposure frame. A structure that is perceived as being green 116will reflect back pulsed green 106 light. The reflection off the greenstructure results in sensed green 107 by the pixel array 122 followingthe pulsed green 106 emission. The data sensed by the pixel array 122results in a green exposure frame. A structure that is perceived asbeing blue 118 will reflect back pulsed blue 108 light. The reflectionoff the blue structure results in sensed blue 109 by the pixel array 122following the pulsed blue 108 emission. The data sensed by the pixelarray 122 results in a blue exposure frame.

When a structure is a combination of colors, the structure will reflectback a combination of the pulsed red 104, pulsed green 106, and/orpulsed blue 108 emissions. For example, a structure that is perceived asbeing purple will reflect back light from the pulsed red 104 and pulsedblue 108 emissions. The resulting data sensed by the pixel array 122will indicate that light was reflected in the same region following thepulsed red 104 and pulsed blue 108 emissions. When the resultant redexposure frame and blue exposure frames are combined to form the RGBimage frame, the RGB image frame will indicate that the structure ispurple.

In an embodiment where the light deficient environment 112 includes afluorescent reagent or dye or includes one or more fluorescentstructures, tissues, or other elements, the pulsing scheme may includethe emission of a certain fluorescence excitation wavelength. Thecertain fluorescence excitation wavelength may be selected to fluorescea known fluorescent reagent, dye, or other structure. The fluorescentstructure will be sensitive to the fluorescence excitation wavelengthand will emit a fluorescence relaxation wavelength. The fluorescencerelaxation wavelength will be sensed by the pixel array 122 followingthe emission of the fluorescence excitation wavelength. The data sensedby the pixel array 122 results in a fluorescence exposure frame. Thefluorescence exposure frame may be combined with multiple other exposureframes to form an image frame. The data in the fluorescence exposureframe may be overlaid on an RGB image frame that includes data from ared exposure frame, a green exposure frame, and a blue exposure frame.

In an embodiment where the light deficient environment 112 includesstructures, tissues, or other materials that emit a spectral response tocertain partitions of the electromagnetic spectrum, the pulsing schememay include the emission of a hyperspectral partition of electromagneticradiation for the purpose of eliciting the spectral response from thestructures, tissues, or other materials present in the light deficientenvironment 112. The spectral response includes the emission orreflection of certain wavelengths of electromagnetic radiation. Thespectral response can be sensed by the pixel array 122 and result in ahyperspectral exposure frame. The hyperspectral exposure frame may becombined with multiple other exposure frames to form an image frame. Thedata in the hyperspectral exposure frame may be overlaid on an RGB imageframe that includes data from a red exposure frame, a green exposureframe, and a blue exposure frame.

In an embodiment, the pulsing scheme includes the emission of a lasermapping or tool tracking pattern. The reflected electromagneticradiation sensed by the pixel array 122 following the emission of thelaser mapping or tool tracking pattern results in a laser mappingexposure frame. The data in the laser mapping exposure frame may beprovided to a corresponding system to identify, for example, distancesbetween tools present in the light deficient environment 112, athree-dimensional surface topology of a scene in the light deficientenvironment 112, distances, dimensions, or positions of structures orobjects within the scene, and so forth. This data may be overlaid on anRGB image frame or otherwise provided to a user of the system.

The emitter 102 may be a laser emitter that is capable of emittingpulsed red 104 light for generating sensed red 105 data for identifyingred 114 elements within the light deficient environment 112. The emitter102 is further capable of emitting pulsed green 106 light for generatingsensed green 107 data for identifying green 116 elements within thelight deficient environment. The emitter 102 is further capable ofemitting pulsed blue 108 light for generating sensed blue 109 data foridentifying blue 118 elements within the light deficient environment.The emitter 102 is further capable of emitting pulsed fluorescenceexcitation 110 wavelength(s) of electromagnetic radiation foridentifying a fluorescent reagent 120 within the light deficientenvironment 112. The fluorescent reagent 120 is identified by excitingthe fluorescent reagent 120 with the pulsed fluorescence excitation 110light and then sensing (by the pixel array 122) the fluorescencerelaxation 111 wavelength for that particular fluorescent reagent 120.The emitter 102 is capable of emitting the pulsed red 104, pulsed green106, pulsed blue 108, and pulsed fluorescence excitation 110 wavelengthsin any desired sequence.

The pixel array 122 senses reflected electromagnetic radiation. Each ofthe sensed red 105, the sensed green 107, the sensed blue 109, and thesensed fluorescence relaxation 111 data can be referred to as an“exposure frame.” Each exposure frame is assigned a specific color orwavelength partition, wherein the assignment is based on the timing ofthe pulsed color or wavelength partition from the emitter 102. Theexposure frame in combination with the assigned specific color orwavelength partition may be referred to as a dataset. Even though thepixels 122 are not color-dedicated, they can be assigned a color for anygiven dataset based on a priori information about the emitter.

For example, during operation, after pulsed red 104 light is pulsed inthe light deficient environment 112, the pixel array 122 sensesreflected electromagnetic radiation. The reflected electromagneticradiation results in an exposure frame, and the exposure frame iscatalogued as sensed red 105 data because it corresponds in time withthe pulsed red 104 light. The exposure frame in combination with anindication that it corresponds in time with the pulsed red 104 light isthe “dataset.” This is repeated for each partition of electromagneticradiation emitted by the emitter 102. The data created by the pixelarray 122 includes the sensed red 105 exposure frame identifying red 114components in the light deficient environment and corresponding in timewith the pulsed red 104 light. The data further includes the sensedgreen 107 exposure frame identifying green 116 components in the lightdeficient environment and corresponding in time with the pulsed green106 light. The data further includes the sensed blue 109 exposure frameidentifying blue 118 components in the light deficient environment andcorresponding in time with the pulsed blue 108 light. The data furtherincludes the sensed fluorescence relaxation 111 exposure frameidentifying the fluorescent reagent 120 and corresponding in time withthe pulsed fluorescence excitation 110 wavelength(s) of light.

In one embodiment, three datasets representing RED, GREEN and BLUEelectromagnetic pulses are combined to form a single image frame. Thus,the information in a red exposure frame, a green exposure frame, and ablue exposure frame are combined to form a single RGB image frame. Oneor more additional datasets representing other wavelength partitions maybe overlaid on the single RGB image frame. The one or more additionaldatasets may represent, for example, fluorescence imaging responsive tothe pulsed excitation 110 wavelength between 770 nm and 790 nm andbetween 795 nm and 815 nm.

It will be appreciated that the disclosure is not limited to anyparticular color combination or any particular electromagneticpartition, and that any color combination or any electromagneticpartition may be used in place of RED, GREEN and BLUE, such as Cyan,Magenta and Yellow; Ultraviolet; infrared; any combination of theforegoing, or any other color combination, including all visible andnon-visible wavelengths, without departing from the scope of thedisclosure. In the figure, the light deficient environment 112 to beimaged includes red 114, green 116, and blue 118 portions, and furtherincludes a fluorescent reagent 120. As illustrated in the figure, thereflected light from the electromagnetic pulses only contains the datafor the portion of the object having the specific color that correspondsto the pulsed color partition. Those separate color (or color interval)datasets can then be used to reconstruct the image by combining thedatasets at 126. The information in each of the multiple exposure frames(i.e., the multiple datasets) may be combined by a controller 124, acontrol unit, a camera control unit, the image sensor, an image signalprocessing pipeline, or some other computing resource that isconfigurable to process the multiple exposure frames and combine thedatasets at 126. The datasets may be combined to generate the singleimage frame within the endoscope unit itself or offsite by some otherprocessing resource.

FIG. 2 is a system 200 for providing illumination to a light deficientenvironment, such as for endoscopic imaging. The system 200 may be usedin combination with any of the systems, methods, or devices disclosedherein. The system 200 includes an emitter 202, a controller 204, ajumper waveguide 206, a waveguide connector 208, a lumen waveguide 210,a lumen 212, and an image sensor 214 with accompanying opticalcomponents (such as a lens). The emitter 202 (may be genericallyreferred to as a “light source”) generates light that travels throughthe jumper waveguide 206 and the lumen waveguide 210 to illuminate ascene at a distal end of the lumen 212. The emitter 202 may be used toemit any wavelength of electromagnetic energy including visiblewavelengths, infrared, ultraviolet, hyperspectral, fluorescenceexcitation, laser mapping pulsing schemes, or other wavelengths. Thelumen 212 may be inserted into a patient's body for imaging, such asduring a procedure or examination. The light is output as illustrated bydashed lines 216. A scene illuminated by the light may be captured usingthe image sensor 214 and displayed for a doctor or some other medicalpersonnel. The controller 204 may provide control signals to the emitter202 to control when illumination is provided to a scene. In oneembodiment, the emitter 202 and controller 204 are located within acamera control unit (CCU) or external console to which an endoscope isconnected. If the image sensor 214 includes a CMOS sensor, light may beperiodically provided to the scene in a series of illumination pulsesbetween readout periods of the image sensor 214 during what is known asa blanking period. Thus, the light may be pulsed in a controlled mannerto avoid overlapping into readout periods of the image pixels in a pixelarray of the image sensor 214.

In one embodiment, the lumen waveguide 210 includes one or more opticalfibers. The optical fibers may be made of a low-cost material, such asplastic to allow for disposal of the lumen waveguide 210 and/or otherportions of an endoscope. In one embodiment, the lumen waveguide 210 isa single glass fiber having a diameter of 500 microns. The jumperwaveguide 206 may be permanently attached to the emitter 202. Forexample, a jumper waveguide 206 may receive light from an emitter withinthe emitter 202 and provide that light to the lumen waveguide 210 at thelocation of the connector 208. In one embodiment, the jumper waveguide106 includes one or more glass fibers. The jumper waveguide may includeany other type of waveguide for guiding light to the lumen waveguide210. The connector 208 may selectively couple the jumper waveguide 206to the lumen waveguide 210 and allow light within the jumper waveguide206 to pass to the lumen waveguide 210. In one embodiment, the lumenwaveguide 210 is directly coupled to a light source without anyintervening jumper waveguide 206.

The image sensor 214 includes a pixel array. In an embodiment, the imagesensor 214 includes two or more pixel arrays for generating athree-dimensional image. The image sensor 214 may constitute two moreimage sensors that each have an independent pixel array and can operateindependent of one another. The pixel array of the image sensor 214includes active pixels and optical black (“OB”) or optically blindpixels. The active pixels may be clear “color agnostic” pixels that arecapable of sensing imaging data for any wavelength of electromagneticradiation. The optical black pixels are read during a blanking period ofthe pixel array when the pixel array is “reset” or calibrated. In anembodiment, light is pulsed during the blanking period of the pixelarray when the optical black pixels are being read. After the opticalblack pixels have been read, the active pixels are read during a readoutperiod of the pixel array. The active pixels may be charged by theelectromagnetic radiation that is pulsed during the blanking period suchthat the active pixels are ready to be read by the image sensor duringthe readout period of the pixel array.

FIG. 2A is a schematic diagram of complementary system hardware such asa special purpose or general-purpose computer. Implementations withinthe scope of the present disclosure may also include physical and othernon-transitory computer readable media for carrying or storing computerexecutable instructions and/or data structures. Such computer readablemedia can be any available media that can be accessed by a generalpurpose or special purpose computer system. Computer readable media thatstores computer executable instructions are computer storage media(devices). Computer readable media that carry computer executableinstructions are transmission media. Thus, by way of example, and notlimitation, implementations of the disclosure can comprise at least twodistinctly different kinds of computer readable media: computer storagemedia (devices) and transmission media.

Computer storage media (devices) includes RAM, ROM, EEPROM, CD-ROM,solid state drives (“SSDs”) (e.g., based on RAM), Flash memory,phase-change memory (“PCM”), other types of memory, other optical diskstorage, magnetic disk storage or other magnetic storage devices, or anyother medium which can be used to store desired program code means inthe form of computer executable instructions or data structures andwhich can be accessed by a general purpose or special purpose computer.

A “network” is defined as one or more data links that enable thetransport of electronic data between computer systems and/or modulesand/or other electronic devices. In an implementation, a sensor andcamera control unit may be networked to communicate with each other, andother components, connected over the network to which they areconnected. When information is transferred or provided over a network oranother communications connection (either hardwired, wireless, or acombination of hardwired or wireless) to a computer, the computerproperly views the connection as a transmission medium. Transmissionsmedia can include a network and/or data links, which can be used tocarry desired program code means in the form of computer executableinstructions or data structures and which can be accessed by a generalpurpose or special purpose computer. Combinations of the above shouldalso be included within the scope of computer readable media.

Further, upon reaching various computer system components, program codemeans in the form of computer executable instructions or data structuresthat can be transferred automatically from transmission media tocomputer storage media (devices) (or vice versa). For example, computerexecutable instructions or data structures received over a network ordata link can be buffered in RAM within a network interface module(e.g., a “NIC”), and then eventually transferred to computer system RAMand/or to less volatile computer storage media (devices) at a computersystem. RAM can also include solid state drives (SSDs or PCIx based realtime memory tiered storage, such as FusionIO). Thus, it should beunderstood that computer storage media (devices) can be included incomputer system components that also (or even primarily) utilizetransmission media.

Computer executable instructions comprise, for example, instructions anddata which, when executed by one or more processors, cause ageneral-purpose computer, special purpose computer, or special purposeprocessing device to perform a certain function or group of functions.The computer executable instructions may be, for example, binaries,intermediate format instructions such as assembly language, or evensource code. Although the subject matter has been described in languagespecific to structural features and/or methodological acts, it is to beunderstood that the subject matter defined in the appended claims is notnecessarily limited to the described features or acts described above.Rather, the described features and acts are disclosed as example formsof implementing the claims.

Those skilled in the art will appreciate that the disclosure may bepracticed in network computing environments with many types of computersystem configurations, including, personal computers, desktop computers,laptop computers, message processors, control units, camera controlunits, hand-held devices, hand pieces, multi-processor systems,microprocessor-based or programmable consumer electronics, network PCs,minicomputers, mainframe computers, mobile telephones, PDAs, tablets,pagers, routers, switches, various storage devices, and the like. Itshould be noted that any of the above-mentioned computing devices may beprovided by or located within a brick and mortar location. Thedisclosure may also be practiced in distributed system environmentswhere local and remote computer systems, which are linked (either byhardwired data links, wireless data links, or by a combination ofhardwired and wireless data links) through a network, both performtasks. In a distributed system environment, program modules may belocated in both local and remote memory storage devices.

Further, where appropriate, functions described herein can be performedin one or more of: hardware, software, firmware, digital components, oranalog components. For example, one or more application specificintegrated circuits (ASICs) or field programmable gate arrays (FPGAs)can be programmed to carry out one or more of the systems and proceduresdescribed herein. Certain terms are used throughout the followingdescription and Claims to refer to particular system components. As oneskilled in the art will appreciate, components may be referred to bydifferent names. This document does not intend to distinguish betweencomponents that differ in name, but not function.

FIG. 2A is a block diagram illustrating an example computing device 250.Computing device 250 may be used to perform various procedures, such asthose discussed herein. Computing device 250 can function as a server, aclient, or any other computing entity. Computing device 250 can performvarious monitoring functions as discussed herein, and can execute one ormore application programs, such as the application programs describedherein. Computing device 250 can be any of a wide variety of computingdevices, such as a desktop computer, a notebook computer, a servercomputer, a handheld computer, camera control unit, tablet computer andthe like.

Computing device 250 includes one or more processor(s) 252, one or morememory device(s) 254, one or more interface(s) 256, one or more massstorage device(s) 258, one or more Input/Output (I/O) device(s) 260, anda display device 280 all of which are coupled to a bus 262. Processor(s)252 include one or more processors or controllers that executeinstructions stored in memory device(s) 254 and/or mass storagedevice(s) 258. Processor(s) 252 may also include various types ofcomputer readable media, such as cache memory.

Memory device(s) 254 include various computer readable media, such asvolatile memory (e.g., random access memory (RAM) 264) and/ornonvolatile memory (e.g., read-only memory (ROM) 266). Memory device(s)254 may also include rewritable ROM, such as Flash memory.

Mass storage device(s) 258 include various computer readable media, suchas magnetic tapes, magnetic disks, optical disks, solid-state memory(e.g., Flash memory), and so forth. As shown in FIG. 2, a particularmass storage device is a hard disk drive 274. Various drives may also beincluded in mass storage device(s) 258 to enable reading from and/orwriting to the various computer readable media. Mass storage device(s)258 include removable media 276 and/or non-removable media.

I/O device(s) 260 include various devices that allow data and/or otherinformation to be input to or retrieved from computing device 250.Example I/O device(s) 260 include digital imaging devices,electromagnetic sensors and emitters, cursor control devices, keyboards,keypads, microphones, monitors or other display devices, speakers,printers, network interface cards, modems, lenses, CCDs or other imagecapture devices, and the like.

Display device 280 includes any type of device capable of displayinginformation to one or more users of computing device 250. Examples ofdisplay device 280 include a monitor, display terminal, video projectiondevice, and the like.

Interface(s) 256 include various interfaces that allow computing device250 to interact with other systems, devices, or computing environments.Example interface(s) 256 may include any number of different networkinterfaces 270, such as interfaces to local area networks (LANs), widearea networks (WANs), wireless networks, and the Internet. Otherinterface(s) include user interface 268 and peripheral device interface272. The interface(s) 256 may also include one or more user interfaceelements 268. The interface(s) 256 may also include one or moreperipheral interfaces such as interfaces for printers, pointing devices(mice, track pad, etc.), keyboards, and the like.

Bus 262 allows processor(s) 252, memory device(s) 254, interface(s) 256,mass storage device(s) 258, and I/O device(s) 260 to communicate withone another, as well as other devices or components coupled to bus 262.Bus 262 represents one or more of several types of bus structures, suchas a system bus, PCI bus, IEEE 1394 bus, USB bus, and so forth.

For purposes of illustration, programs and other executable programcomponents are shown herein as discrete blocks, although it isunderstood that such programs and components may reside at various timesin different storage components of computing device 250 and are executedby processor(s) 252. Alternatively, the systems and procedures describedherein can be implemented in hardware, or a combination of hardware,software, and/or firmware. For example, one or more application specificintegrated circuits (ASICs) or field programmable gate arrays (FPGAs)can be programmed to carry out one or more of the systems and proceduresdescribed herein.

FIG. 3A illustrates the operational cycles of a sensor used in rollingreadout mode or during the sensor readout 300. The frame readout periodmay start at and may be represented by vertical line 310. The readoutperiod 302 is represented by the diagonal or slanted line. The sensormay be read out on a row by row basis, the top of the downwards slantededge being the sensor top row 312 and the bottom of the downwardsslanted edge being the sensor bottom row 314. The time between the lastrow readout and the next readout period may be called the blankingperiod 316. It should be noted that some of the sensor pixel rows mightbe covered with a light shield (e.g., a metal coating or any othersubstantially black layer of another material type). These covered pixelrows may be referred to as optical black rows 318 and 320. Optical blackrows 318 and 320 may be used as input for correction algorithms. Asshown in FIG. 3A, these optical black rows 318 and 320 may be located onthe top of the pixel array or at the bottom of the pixel array or at thetop and the bottom of the pixel array.

FIG. 3B illustrates a process of controlling the amount ofelectromagnetic radiation, e.g., light, that is exposed to a pixel,thereby integrated or accumulated by the pixel. It will be appreciatedthat photons are elementary particles of electromagnetic radiation.Photons are integrated, absorbed, or accumulated by each pixel andconverted into an electrical charge or current. An electronic shutter orrolling shutter (shown by dashed line 322) may be used to start theintegration time by resetting the pixel. The light will then integrateuntil the next readout period. The position of the electronic shutter322 can be moved between two readout periods 302 to control the pixelsaturation for a given amount of light. It should be noted that thistechnique allows for a constant integration time between two differentlines but introduces a delay when moving from top to bottom rows.

FIG. 3C illustrates the case where the electronic shutter 322 has beenremoved. In this configuration, the integration of the incoming lightmay start during the readout period 302 and may end at the next readoutperiod 302, which also defines the start of the next integration.

FIG. 3D shows a configuration without an electronic shutter 322, butwith a controlled and pulsed light 330 during the blanking period 316.This ensures that all rows see the same light issued from the same lightpulse 330. In other words, each row will start its integration in a darkenvironment, which may be at the optical black back row 320 of read outframe (m) for a maximum light pulse width, and will then receive a lightstrobe and will end its integration in a dark environment, which may beat the optical black front row 318 of the next succeeding read out frame(m+1) for a maximum light pulse width. In the FIG. 3D example, the imagegenerated from the light pulse will be solely available during frame(m+1) readout without any interference with frames (m) and (m+2). Itshould be noted that the condition to have a light pulse to be read outonly in one frame and not interfere with neighboring frames is to havethe given light pulse firing during the blanking period 316. Because theoptical black rows 318, 320 are insensitive to light, the optical blackback rows 320 time of frame (m) and the optical black front rows 318time of frame (m+1) can be added to the blanking period 316 to determinethe maximum range of the firing time of the light pulse 330.

As illustrated in the FIG. 3A, a sensor may be cycled many times toreceive data for each pulsed color or wavelength (e.g., Red, Green,Blue, or other wavelength on the electromagnetic spectrum). Each cyclemay be timed. In an embodiment, the cycles may be timed to operatewithin an interval of 16.67 ms. In another embodiment, the cycles may betimed to operate within an interval of 8.3 ms. It will be appreciatedthat other timing intervals are contemplated by the disclosure and areintended to fall within the scope of this disclosure.

FIG. 4A graphically illustrates the operation of an embodiment of anelectromagnetic emitter. An emitter may be timed to correspond with thecycles of a sensor, such that electromagnetic radiation is emittedwithin the sensor operation cycle and/or during a portion of the sensoroperation cycle. FIG. 4A illustrates Pulse 1 at 402, Pulse 2 at 404, andPulse 3 at 406. In an embodiment, the emitter may pulse during thereadout period 302 of the sensor operation cycle. In an embodiment, theemitter may pulse during the blanking period 316 of the sensor operationcycle. In an embodiment, the emitter may pulse for a duration that isduring portions of two or more sensor operational cycles. In anembodiment, the emitter may begin a pulse during the blanking period316, or during the optical black portion 320 of the readout period 302,and end the pulse during the readout period 302, or during the opticalblack portion 318 of the readout period 302 of the next succeedingcycle. It will be understood that any combination of the above isintended to fall within the scope of this disclosure as long as thepulse of the emitter and the cycle of the sensor correspond.

FIG. 4B graphically represents varying the duration and magnitude of theemitted electromagnetic pulse (e.g., Pulse 1 at 412, Pulse 2 at 414, andPulse 3 at 416) to control exposure. An emitter having a fixed outputmagnitude may be pulsed during any of the cycles noted above in relationto FIGS. 3D and 4A for an interval to provide the needed electromagneticenergy to the pixel array. An emitter having a fixed output magnitudemay be pulsed at a longer interval of time, thereby providing moreelectromagnetic energy to the pixels or the emitter may be pulsed at ashorter interval of time, thereby providing less electromagnetic energy.Whether a longer or shorter interval time is needed depends upon theoperational conditions.

In contrast to adjusting the interval of time the emitter pulses a fixedoutput magnitude, the magnitude of the emission itself may be increasedto provide more electromagnetic energy to the pixels. Similarly,decreasing the magnitude of the pulse provides less electromagneticenergy to the pixels. It should be noted that an embodiment of thesystem may have the ability to adjust both magnitude and durationconcurrently, if desired. Additionally, the sensor may be adjusted toincrease its sensitivity and duration as desired for optimal imagequality. FIG. 4B illustrates varying the magnitude and duration of thepulses. In the illustration, Pulse 1 at 412 has a higher magnitude orintensity than either Pulse 2 at 414 or Pulse 3 at 416. Additionally,Pulse 1 at 412 has a shorter duration than Pulse 2 at 414 or Pulse 3 at416, such that the electromagnetic energy provided by the pulse isillustrated by the area under the pulse shown in the illustration. Inthe illustration, Pulse 2 at 414 has a relatively low magnitude orintensity and a longer duration when compared to either Pulse 1 at 412or Pulse 3 at 416. Finally, in the illustration, Pulse 3 at 416 has anintermediate magnitude or intensity and duration, when compared to Pulse1 at 412 and Pulse 2 at 414.

FIG. 5 is a graphical representation of an embodiment of the disclosurecombining the operational cycles, the electromagnetic emitter, and theemitted electromagnetic pulses of FIGS. 3A-3D and 4A to demonstrate theimaging system during operation in accordance with the principles andteachings of the disclosure. As can be seen in the figure, theelectromagnetic emitter pulses the emissions primarily during theblanking period 316 of the image sensor such that the pixels will becharged and ready to read during the readout period 302 of the imagesensor cycle. The dashed lines in FIG. 5 represent the pulses ofelectromagnetic radiation (from FIG. 4A). The pulses of electromagneticradiation are primarily emitted during the blanking period 316 of theimage sensor but may overlap with the readout period 302 of the imagesensor.

An exposure frame includes the data read by the pixel array of the imagesensor during a readout period 302. The exposure frame may be combinedwith an indication of what type of pulse was emitted by the emitterprior to the readout period 302. The combination of the exposure frameand the indication of the pulse type may be referred to as a dataset.Multiple exposure frames may be combined to generate a black-and-whiteor RGB color image. Additionally, hyperspectral, fluorescence, and/orlaser mapping imaging data may be overlaid on a black-and-white or RGBimage.

In an embodiment, an exposure frame is the data sensed by the pixelarray during the readout period 302 that occurs subsequent to a blankingperiod 316. The emission of electromagnetic radiation is emitted duringthe blanking period 316. In an embodiment, a portion of the emission ofelectromagnetic radiation overlaps the readout period 302. The blankingperiod 316 occurs when optical black pixels of the pixel array are beingread and the readout period 302 occurs when active pixels of the pixelarray are being read. The blanking period 316 may overlap the readoutperiod 302.

FIGS. 6A and 6B illustrate processes for recording an image frame.Multiple image frames may be strung together to generate a video stream.A single image frame may include data from multiple exposure frames,wherein an exposure frame is the data sensed by a pixel array subsequentto an emission of electromagnetic radiation. FIG. 6A illustrates atraditional process that is typically implemented with a color imagesensor having a color filter array (CFA) for filtering out certainwavelengths of light per pixel. FIG. 6B is a process that is disclosedherein and can be implemented with a monochromatic “color agnostic”image sensor that is receptive to all wavelengths of electromagneticradiation.

The process illustrated in FIG. 6A occurs from time t(0) to time t(1).The process begins with a white light emission 602 and sensing whitelight 604. The image is processed and displayed at 606 based on thesensing at 604.

The process illustrated in FIG. 6B occurs from time t(0) to time t(1).The process begins with an emission of green light 612 and sensingreflected electromagnetic radiation 614 subsequent to the emission ofgreen light 612. The process continues with an emission of red light 616and sensing reflected electromagnetic radiation 618 subsequent to theemission of red light 616. The process continues with an emission ofblue light 620 and sensing reflected electromagnetic radiation 622subsequent to the emission of blue light 620. The process continues withone or more emissions of a fluorescence excitation wavelengths 624 andsensing reflected electromagnetic energy 626 subsequent to each of theone or more emissions of fluorescence excitation wavelengths ofelectromagnetic radiation 624. The image is processed and displayed at628 based on each of the sensed reflected electromagnetic energyinstances 614, 618, 622, and 626.

The process illustrated in FIG. 6B provides a higher resolution imageand provides a means for generating an RGB image that further includesfluorescence imaging data. When partitioned spectrums of light are used,(as in FIG. 6B) a sensor can be made sensitive to all wavelengths ofelectromagnetic energy. In the process illustrated in FIG. 6B, themonochromatic pixel array is instructed that it is sensingelectromagnetic energy from a predetermined partition of the fullspectrum of electromagnetic energy in each cycle. Therefore, to form animage the sensor need only be cycled with a plurality of differingpartitions from within the full spectrum of light. The final image isassembled based on the multiple cycles. Because the image from eachcolor partition frame cycle has a higher resolution (compared with a CFApixel array), the resultant image created when the partitioned lightframes are combined also has a higher resolution. In other words,because each and every pixel within the array (instead of, at most,every second pixel in a sensor with a CFA) is sensing the magnitudes ofenergy for a given pulse and a given scene, just fractions of timeapart, a higher resolution image is created for each scene.

As can be seen graphically in the embodiments illustrated in FIGS. 6Aand 6B between times t(0) and t(1), the sensor for the partitionedspectrum system in FIG. 6B has cycled at least four times for every oneof the full spectrum system in FIG. 6A. In an embodiment, a displaydevice (LCD panel) operates at 50-60 frames per second. In such anembodiment, the partitioned light system in FIG. 6B may operate at200-240 frames per second to maintain the continuity and smoothness ofthe displayed video. In other embodiments, there may be differentcapture and display frame rates. Furthermore, the average capture ratecould be any multiple of the display rate.

In an embodiment, it may be desired that not all partitions berepresented equally within the system frame rate. In other words, notall light sources have to be pulsed with the same regularity so as toemphasize and de-emphasize aspects of the recorded scene as desired bythe users. It should also be understood that non-visible and visiblepartitions of the electromagnetic spectrum may be pulsed together withina system with their respective data value being stitched into the videooutput as desired for display to a user.

An embodiment may comprise a pulse cycle pattern as follows:

-   -   i. Green pulse;    -   ii. Red pulse;    -   iii. Blue pulse;    -   iv. Green pulse;    -   v. Red pulse;    -   vi. Blue pulse;    -   vii. Fluorescence excitation pulse;    -   viii. (Repeat)

An embodiment may comprise a pulse cycle pattern as follows:

-   -   i. Luminance pulse;    -   ii. Red chrominance pulse;    -   iii. Luminance pulse;    -   iv. Blue Chrominance pulse;    -   v. Fluorescence excitation pulse;    -   vi. (Repeat)

An embodiment may comprise a pulse cycle pattern as follows:

-   -   i. Luminance pulse;    -   ii. Red chrominance pulse;    -   iii. Luminance pulse;    -   iv. Blue Chrominance pulse;    -   v. Luminance pulse;    -   vi. Red chrominance pulse;    -   vii. Luminance pulse;    -   viii. Blue Chrominance pulse;    -   ix. Fluorescence excitation pulse;    -   x. (Repeat)

As can be seen in the example, a fluorescence excitation partition maybe pulsed at a rate differing from the rates of the other partitionpulses. This may be done to emphasize a certain aspect of the scene,with the fluorescence imaging data simply being overlaid with the otherdata in the video output to make the desired emphasis. It should benoted that the addition of a fluorescence partition on top of the RED,GREEN, and BLUE partitions does not necessarily require the serializedsystem to operate at four times the rate of a full spectrum non-serialsystem because every partition does not have to be represented equallyin the pulse pattern. As seen in the embodiment, the addition of apartition pulse that is represented less in a pulse pattern(fluorescence excitation in the above example), would result in anincrease of less than 20% of the cycling speed of the sensor toaccommodate the irregular partition sampling.

In various embodiments, the pulse cycle pattern may further include anyof the following wavelengths in any suitable order. Such wavelengths maybe particularly suited for exciting a fluorescent reagent to generatefluorescence imaging data by sensing the relaxation emission of thefluorescent reagent based on a fluorescent reagent relaxation emission:

-   -   i. 770±20 nm;    -   ii. 770±10 nm;    -   iii. 770±5 nm;    -   iv. 790±20 nm;    -   v. 790±10 nm;    -   vi. 790±5 nm;    -   vii. 795±20 nm;    -   viii. 795±10 nm;    -   ix. 795±5 nm;    -   x. 815±20 nm;    -   xi. 815±10 nm;    -   xii. 815±5 nm;    -   xiii. 770 nm to 790 nm; and/or    -   xiv. 795 nm to 815 nm.

The partition cycles may be divided so as to accommodate or approximatevarious imaging and video standards. In an embodiment, the partitioncycles comprise pulses of electromagnetic energy in the Red, Green, andBlue spectrum as follows as illustrated best in FIGS. 7A-7D. The timingrelationship between the emission of pulses of electromagnetic radiationby the emitter, and the readout of the pixel array is furtherillustrated in FIGS. 7A-7D.

In an embodiment, the emitter emits one or more hyperspectral emissionsfor eliciting a spectral response. The hyperspectral emissions includeone or more of electromagnetic radiation having a wavelength from about513-545 nm, from about 565-585 nm, and/or from about 900-1000 nm. Insuch an embodiment, the coherent light source 802 includes at least onelaser emitter for the 513-545 nm partition, at least one laser emitterfor the 565-585 partition, and at least one laser emitter for the900-1000 nm partition. It should be appreciated that additionalhyperspectral emissions for eliciting a spectral response can be emittedwithout departing from the scope of the disclosure.

In an embodiment, the emitter emits one or more fluorescence excitationemissions for fluorescing a reagent. The fluorescence excitationemissions include one or more of electromagnetic radiation having awavelength from about 460-470 nm, 529-537 nm. 633-643 nm, 775-785 nm,800-810 nm, 970-980 nm, 575-579 nm, 519-527 nm, 770-790 nm, and/or795-815 nm. In such an embodiment, the coherent light source 802 mayinclude at least one laser emitter for each of the aforementionedpartitions of electromagnetic radiation. It should be appreciated thatadditional fluorescence excitation emissions for fluorescing a reagentcan be emitted without departing from the scope of the disclosure.

In FIG. 7A, the different light intensities have been achieved bymodulating the light pulse width or duration within the working rangeshown by the vertical grey dashed lines. FIG. 7A illustrates the generaltiming relationships within a four-frame cycle, between pulsed mixturesof three wavelengths and the readout cycle of the pixel array of theimage sensor. In an embodiment, there are three monochromatic pulsedlight sources under the control of the controller. Periodic sequences ofmonochromatic red, monochromatic green, and monochromatic blue exposureframes are captured, e.g. with an R-G-B-G pulsing pattern and assembledinto an sRGB image frame by the image signal processor chain.

In FIG. 7B, the different light intensities have been achieved bymodulating the light power or the power of the electromagnetic emitter,which may be a laser or LED emitter, but keeping the pulse width orduration constant.

FIG. 7C shows the case where both the light power and the light pulsewidth are being modulated, leading to greater flexibility. The partitioncycles may use Cyan Magenta Yellow (CMY), infrared, ultraviolet,hyperspectral, and fluorescence using a non-visible pulse source mixedwith visible pulse sources and any other color space required to producean image or approximate a desired video standard that is currently knownor yet to be developed. It should also be understood that a system maybe able to switch between the color spaces on the fly to provide thedesired image output quality.

In an embodiment using color spaces Green-Blue-Green-Red (as seen inFIG. 7D) it may be desirous to pulse the luminance components more oftenthan the chrominance components because users are generally moresensitive to light magnitude differences than to light colordifferences. This principle can be exploited using a monochromatic imagesensor as illustrated in FIG. 7D. In FIG. 7D, green, which contains themost luminance information, may be pulsed more often or with moreintensity in a (G-B-G-R-G-B-G-R . . . ) scheme to obtain the luminancedata. Such a configuration would create a video stream that hasperceptively more detail, without creating and transmittingunperceivable data.

In an embodiment, all three sources of light are pulsed in unison withlight energies that are modulated to provide pure luminance informationin the same exposure frame. The light energies may be modulatedaccording to color transformation coefficients that convert from RGBcolor space to YCbCr color space. It should be appreciated that thecolor transformation may be implemented according to any suitablestandard such as the ITU-R BT.709 HD standard, the ITU-R BT.601standard, the ITU-R BT.2020 standard, or any other suitable standard orformula. The conversion may be performed according to the ITU-R BT.709HD standard as follows:

$\begin{bmatrix}Y \\{Cb} \\{Cr}\end{bmatrix} = {\begin{bmatrix}R \\G \\B\end{bmatrix}\begin{bmatrix}{{0.1}83} & {{0.6}14} & {{0.0}62} \\{{- {0.1}}01} & {{- {0.3}}39} & {{0.4}39} \\{{0.4}39} & {{- {0.3}}99} & {{- {0.0}}40}\end{bmatrix}}$

In addition to the modulation of luminance information, a full colorimage further requires the red chrominance and blue chrominancecomponents. However, the algorithm applied for the luminance componentcannot be directly applied for chrominance componence because thealgorithm is signed as reflected in the fact that some of the RGBcoefficients are negative. In an embodiment, a degree of luminance isadded so that all of the final pulse energies are a positive value. Aslong as the color fusion process in the image signal processor is awareof the composition of the chrominance exposure frames, they can bedecoded by subtracting the appropriate amount of luminance from aneighboring frame. The pulse energy proportions are given by:

Y=0.183·R+0.614·G+0.062·B

Cb=λ·Y·0.101·R−0.339·G+0.439·B

Cr=δ·Y+0.439·R−0.399·G−0.040·B

where

${{{\lambda \geq \frac{0.339}{0.614}} = 0}{\delta \geq \frac{0.399}{0.614}}} = 0.650$

If the λ factor is equal to 0.552, the red and green components arecancelled. In the case, the blue chrominance information can be providedwith pure blue light. Similarly, if the δ factor is equal to 0.650, theblue and green components are cancelled, and the red chrominanceinformation can be provided with pure red light. This embodiment is aconvenient approximation for digital frame reconstruction.

In an embodiment where white balance is performed in the illuminationdomain, then the modulation is imposed in addition to the white balancemodulation.

In an embodiment, duplicating the pulse of a weaker partition may beused to produce an output that has been adjusted for the weaker pulse.For example, blue laser light is considered weak relative to thesensitivity of silicon-based pixels and is difficult to produce incomparison to the red or green light, and therefore may be pulsed moreoften during a frame cycle to compensate for the weakness of the light.These additional pulses may be done serially over time or by usingmultiple lasers that simultaneously pulse to produce the desiredcompensation effect. It should be noted that by pulsing during ablanking period (time during which the sensor is not reading out thepixel array), the sensor is insensitive to differences/mismatchesbetween lasers of the same kind and simply accumulates the light for thedesired output. In another embodiment, the maximum light pulse range maybe different from frame to frame. This is shown in FIG. 7E, where thelight pulses are different from frame to frame. The sensor may be builtto be able to program different blanking periods with a repeatingpattern of two or three or four or n frames.

In FIG. 7E, four different light pulses are illustrated, and Pulse 1 mayrepeat for example after Pulse 4 and may have a pattern of four frameswith different blanking periods. This technique can be used to place themost powerful partition on the smallest blanking period and thereforeallow the weakest partition to have wider pulse on one of the nextframes without the need of increasing the readout speed. Thereconstructed frame can still have a regular pattern from frame to frameas it is constituted of many pulsed frames.

FIG. 8 illustrates an embodiment of a system 800 for endoscopic imaging.The system includes a handpiece 802 and an endoscope tube 804 that canfreely rotate with respect to one another as illustrated in FIG. 8. Thesystem 800 may further include an electrical cable 806 attached to thehandpiece 802 and a light cable 810 attached to the endoscope tube 804.The system 800 includes an image sensor 808 that may be located withinthe handpiece 802 or at a distal end of the endoscope tube 804 as shownin FIG. 8.

The handpiece 802 is configured to be held by a user or robotic systemwhen the system 800 is in use. The endoscope tube 804 is configured tobe inserted into an environment such that the image sensor 808 cancapture exposure frames of that environment. In a medicalimplementation, for example, the endoscope tube 804 is inserted into abody cavity while the handpiece 802 is held and operated by a medicalpractitioner. The system 800 may be in electrical communication with adisplay such that the user can view a video stream depicting the imagesbeing captured by the image sensor 808 in real-time.

In some instances, it is desirable for the image horizon on the videostream to remain constant during operation even when the handpiece 802is rotated. Alternatively, the user may expect the image orientation inthe video stream to change when the user rotates the handpiece 802. Ineach instance, some post-processing may be performed on the imagescaptured by the image sensor 808 to ensure that the image orientationreflects the orientation of the handpiece 802 with respect to the scene.

In the system 800, the image sensor 808 is rigidly coupled to a lensstack, and each of the image sensor 808 and the lens stack is rigidlycoupled to the endoscope tube 804. The endoscope tube 804 may consist ofa single tube. The orientation of images captured by the image sensorcan be rotated in post-processing in the image signal processingpipeline (ISP). The ISP calculates a digital representation of the angleof the endoscope tube 804 with respect to the handpiece 802 that iscontinuously available during operation.

In an alternative embodiment different from the system 800 illustratedin FIG. 8, the image sensor is rigidly coupled to the handpiece suchthat rotating the handpiece also rotates the lens stack at the distalend of the endoscope tube. This can be accomplished by incorporating twoconcentric tubes. This alternative embodiment permits a distal prism torotate, and this changes the angle of view for the user while the imagesensor remains at a constant location. This allows the device to be usedin the same manner as expected by a user or operator experienced inusing a conventional rigid endoscopy system. The user or operator mayrotate an outer lumen and thereby change the angle of view while theimage sensor remains in a fixed position. The video stream thenmaintains a constant horizon. The prism may rotate while the imagesensor does not rotate such that the user does not lose orientation.

FIG. 9 illustrates an embodiment of a rotation sensing system 900 foruse in connection with an endoscopic imaging system such as the systems200, 800 illustrated in FIGS. 2 and 8. The rotation sensing system 900includes a rotation sensor 918 for detecting rotation of the endoscopicsystem, and specifically for detecting an angle of rotation of anendoscope tube 804 with respect to the handpiece 802 of the endoscope.

The rotation sensor 918 may be any suitable rotation sensor known in theart. In an embodiment, the rotation sensor 918 is a rotation-detectingHall-effect sensor. In such an embodiment, the rotation sensor 918 maybe located within the handpiece 802 of the endoscope. Further in such anembodiment, the rotation sensing system 900 may further include adiametrically-polarized, magnetic annulus 912. The rotation sensor 918generates a voltage 914, and that voltage 914 can be used to detect anangle of rotation of the diametrically-polarized, magnetic annulus 912.The voltage 914 generated by the rotation sensor 918 can therefore beused to calculate an angle of rotation of the handpiece 802 relative tothe endoscope tube 804 or lumen.

The voltage 914 is fed to an analog to digital converter (ADC) 916. TheADC 916 may alternatively be a digitizer. The digital numberrepresenting the voltage 914 is conveyed to an image signal processing(ISP) pipeline or the camera processing pipeline. In an embodiment, theISP pipeline and/or the camera processing pipeline are integrated in acontroller that is in electrical communication with the emitter and theimage sensor. In an alternative embodiment, the ISP pipeline and/or thecamera processing pipeline are independent of the controller.

In an embodiment the ISP pipeline (or alternatively, the cameraprocessing pipeline) calculate an image rotation transformation. Theimage rotation transformation may be applied to exposure frames capturedby the image sensor. In an embodiment, the image rotation transformationis applied to image frames (such as RGB or YCbCr image frames) thatinclude data from multiple exposure frames, and it should be appreciatedthat this embodiment covers the concept of applying the image rotationtransformation to exposure frames. The image rotation transformation iscalculated based on the angle of rotation detected by the rotationsensor 918. The ISP pipeline may then rotate exposure frames counter tothe angle of rotation to maintain a constant image horizon of a scenebeing imaged by the image sensor.

In an embodiment, calculating the image rotation transformation includesidentifying integer (x,y) coordinates for pixel data in an exposureframe (or an image frame) captured by a pixel of the pixel array. Thiscan be calculated for each of the plurality of pixels in the pixelarray. The calculation further includes applying a rotation kernel tothe integer (x,y) coordinates to transform the integer (x,y) coordinatesto real number pixel coordinates. Again, this can be performed for eachof the plurality of pixels in the pixel array. The calculation furtherincludes truncating the real number pixel coordinates to integer values.If there is blank pixel data in the exposure frame (i.e., pixels thatdid not produce any data), then values can be assigned to the blankpixel data using values of nearby, filled pixel data. The assignedvalues can be calculated using one or more of nearest neighborsubstitution, bilinear interpolation, or bicubic interpolation.

In an embodiment, calculating the image rotation transformation includesidentifying integer (x,y) coordinates for pixel data in an exposureframe (or an image frame) captured by a pixel of the pixel array. Thiscan be calculated for each of the plurality of pixels in the pixelarray, or each of the plurality of “filled pixels” in the pixel arraythat generated “filled data” contributing to the exposure frame. Thecalculation further includes applying an inverse rotation kernel to theinteger (x,y) coordinates to transform the integer (x,y) coordinates toreal number (x,y) coordinates. Again, this can be performed for each ofthe plurality of pixels in the pixel array. The calculation furtherincludes estimating a pixel value at the real number (x,y) coordinatesusing data from one or more closest integer coordinate locations. Thisestimation can be performed using one or more of nearest neighborsubstitution, bilinear interpolation, or bicubic interpolation.

FIG. 10 illustrates an alternative embodiment of a rotation sensingsystem 1000 for use in connection with an endoscopic imaging system suchas the systems 200, 800 illustrated in FIGS. 2 and 8. The rotationsensing system 1000 includes a potentiometer 1020. The potentiometer1020 includes a carbon track or filament 1022 that may be rigidlyattached to the endoscope tube 804. The potentiometer 1020 may furtherinclude a wiper 1024 that may be rigidly attached to the handpiece 802.The resistance between the potentiometer 1020 and the wiper 1024 can bemeasured to calculate the angle of rotation of the endoscope tube 804with respect to the handpiece 802. In an embodiment, a potential dividerarrangement is used for the voltage at the wiper 1024 to provide anangle measurement. In an embodiment, the potentiometer 1020 furtherincludes a carbon filament disposed within the lumen of the endoscope.

The angle of rotation of the endoscope tube 804 with respect to thehandpiece 802 can be calculated based on the resistance between thepotentiometer 1020 and the wiper 1024. The image rotation transformationcan be calculated based on the angle of rotation. The image rotationtransformation can be calculated based on the same steps discussed inconnection with FIG. 9.

FIG. 11 illustrates an embodiment of a rotation sensing system 1100 foruse in connection with an endoscopic imaging system such as the system200, 800 illustrated in FIGS. 2 and 8. The rotation sensing system 1100includes a light source 1126 and a light detector 1128. The light source1126 may include any suitable light source, such as a light emittingdiode (LED) light source. The light detector 1128 may be a photodiode orphototransistor. In an embodiment, the light source 1126 and the lightdetector 1128 are incorporated into or attached to the handpiece 802.The rotation sensing system 1100 may further include a continuousannulus 1130 or disk.

In an embodiment, the continuous annulus 1130 is rigidly attached to theendoscope tube 804. The continuous annulus 1130 may be reflective withvarying degrees of reflectivity as illustrated in FIG. 11. The varyingdegrees of reflectivity may be accomplished with a series of mirrorshaving varying degrees of reflectivity. Each of the series of mirrorsmay be the same size such that the continuous annulus 1130 includesportions of varying reflectivity at regular intervals. The reflectivityof the continuous annulus 1130 may vary linearly with the angle of theendoscope tube 804 with respect to the handpiece 802. In such anembodiment, the angle of rotation of the endoscope tube 804 with respectto the handpiece 802 is measured based on the amount of light from thelight source 1126 that is reflected off the continuous annuls 1130 andback to the light detector 1128.

The image rotation transformation can be calculated based on the angleof rotation. The image rotation transformation can be calculated basedon the same steps discussed in connection with FIG. 9.

FIGS. 12A and 12B illustrate an embodiment of a system 1200 forendoscopic imaging. The system 1200 includes a fixed handpiece 802 witha cylindrical opening on the distal end of the handpiece 802. The system1200 includes an endoscope tube 804. The cylindrical opening of theendoscope tube 804 is restrained in the axial direction but allowed torotate about the axis. In addition to the components mentioned withrespect to FIG. 8, the system 1200 further includes an interfacecomponent 1202 that may be fixed to the handpiece 802, a rotation sleeve1204, a rotation post 1206, supporting electronic and circuitry 1208 forthe image sensor 808, a sensor wire harness 1210, a lens stack 1212, anda lens holder 1214. The lens stack 1212 includes a distal prism locateddistally of the endoscope tube 804.

FIG. 12B shows an embodiment where the combination of the rotationsleeve 1204 and the rotation post 1206 act to constrain the endoscopetube 804 axially. There may be additional material between the interfacecomponent 1202 and the rotation sleeve 1204 to add or reduce friction toachieve a torque that is low enough to be ergonomically pleasing buthigh enough to prevent accidental rotation.

In an embodiment, the rotation post 1206 allows a user to rotate theendoscope tube 804 in a way that is similar to rotating a conventionalrigid endoscope. As the rotation post 1206 rotates, the entire scopeassembly also rotates, including the distal imaging sensor 808 andattached lens stack 1212. As can be seen, the viewing angle dictated bythe distal prism changes and allows the user a broader or different viewof a scene.

For each embodiment of the system shown in FIGS. 8-12B, the rotatingcomponents can be mounted to the rotation sleeve 1204 and the fixedcomponents can be mounted to the handpiece 802.

The digital angle information may be made available to the image signalprocessing (ISP) pipeline where it is sampled periodically (e.g., eachexposure frame and/or each image frame) and quantized appropriately to,e.g., 5° or 10°, units. In order to prevent rapid angular oscillation ofthe final image between adjacent angles, a degree of hysteresis may berequired. One approach is to only allow an image transformation if thesame quantized angle has been observed consistently within the previousn samples, where n would be tuned to the satisfaction of the user.

The image rotation transformation of an image plane through angle θ maybe calculated based on the following transformation:

x ₂=(X ₁ −x ₀)cos θ−(Y ₁ −y ₀)sin θ+x ₀

y ₂=(Y ₁ −y ₀)cos θ+(X ₁ −x ₀)sin θ+y ₀

where (X₁,Y₁) are the original integer pixel coordinates, (x₂,y₂) arethe final real-number pixel coordinates, and (x₀,y₀) marks the axis ofrotation. In general, unless θ is a multiple of 90°, x₂ and y₂ are notintegers. The pixel locations in the final image buffer can be filled bytruncating or rounding the (x₂,y₂) values to integer coordinates (X₂,Y₂)as follows:

X ₂=int(x ₂)

Y ₂=int(y ₂)

In some instances, this approach results in multiple candidate cases andvoid (i.e., blank) pixels. The void pixels can be filled by nearestneighbor substitution or by interpolation (e.g., bilinear or bicubic),requiring an occupancy investigation in their localities.

In an embodiment, the inverse rotation transformation is applied to thefinal integer pixel location to arrive at real-number coordinates withinthe original plane as follows:

x ₁=(X ₂ −x ₀)cos θ+(Y ₂ −y ₀)sin θ+x ₀

y ₁=(Y ₂ −y ₀)cos θ−(X ₂ −x ₀)sin θ+y ₀

An interpolated image content estimate can be calculated because thepixel data within that plane is known to be all integer coordinates.This interpolation can again be bilinear or bicubic. Bilinearinterpolation requires knowing only the closest four pixels, (two ineach dimension). These pixels are identified as (X_(a), Y_(a)), (X_(a),Y_(b)), (X_(b), Y_(a)) and (X_(b), Y_(b)), where:

X _(a)=int(x ₁);X _(b)=int(x ₁)

Y _(a)=int(y ₁);Y _(b)=1+int(y ₁)

The convolution kernel is described by:

$\begin{pmatrix}{\left( {1 - \alpha} \right)\left( {1 - \beta} \right)} & {\beta \left( {1 - \alpha} \right)} \\{\alpha \left( {1 - \beta} \right)} & {\alpha\beta}\end{pmatrix}\quad$

where

α=x ₁ −X _(a)

β=y ₁ −Y _(a)

is in pixel units.

FIGS. 13A-13C each illustrate a light source 1300 having a plurality ofemitters. The light source 1300 can collectively be referred to as an“emitter” herein. The plurality of emitters include a first emitter1302, a second emitter 1304, and a third emitter 1306. Additionalemitters may be included, as discussed further below. The emitters 1302,1304, and 1306 may include one or more laser emitters that emit lighthaving different wavelengths. For example, the first emitter 1302 mayemit a wavelength that is consistent with a blue laser, the secondemitter 1304 may emit a wavelength that is consistent with a greenlaser, and the third emitter 1306 may emit a wavelength that isconsistent with a red laser. For example, the first emitter 1302 mayinclude one or more blue lasers, the second emitter 1304 may include oneor more green lasers, and the third emitter 1306 may include one or morered lasers. The emitters 1302, 1304, 1306 emit laser beams toward acollection region 1308, which may be the location of a waveguide, lens,or other optical component for collecting and/or providing light to awaveguide, such as the jumper waveguide 206 or lumen waveguide 210 ofFIG. 2.

In an implementation, the emitters 1302, 1304, and 1306 emithyperspectral wavelengths of electromagnetic radiation. Certainhyperspectral wavelengths may pierce through tissue and enable a medicalpractitioner to “see through” tissues in the foreground to identifychemical processes, structures, compounds, biological processes, and soforth that are located behind the tissues in the foreground. Thehyperspectral wavelengths may be specifically selected to identify aspecific disease, tissue condition, biological process, chemicalprocess, type of tissue, and so forth that is known to have a certainspectral response.

In an implementation where a patient has been administered a reagent ordye to aid in the identification of certain tissues, structures,chemical reactions, biological processes, and so forth, the emitters1302, 1304, and 1306 may emit wavelength(s) for fluorescing the reagentsor dyes. Such wavelength(s) may be determined based on the reagents ordyes administered to the patient. In such an embodiment, the emittersmay need to be highly precise for emitting desired wavelength(s) tofluoresce or activate certain reagents or dyes.

In an implementation, the emitters 1302, 1304, and 1306 emit a lasermapping pattern for mapping a topology of a scene and/or for calculatingdimensions and distances between objects in the scene. In an embodiment,the endoscopic imaging system is used in conjunction with multiple toolssuch as scalpels, retractors, forceps, and so forth. In such anembodiment, each of the emitters 1302, 1304, and 1306 may emit a lasermapping pattern such that a laser mapping pattern is projected on toeach tool individually. In such an embodiment, the laser mapping datafor each of the tools can be analyzed to identify distances between thetools and other objects in the scene.

In the embodiment of FIG. 13B, the emitters 1302, 1304, 1306 eachdeliver laser light to the collection region 1308 at different angles.The variation in angle can lead to variations where electromagneticenergy is located in an output waveguide. For example, if the lightpasses immediately into a fiber bundle (glass or plastic) at thecollection region 1308, the varying angles may cause different amountsof light to enter different fibers. For example, the angle may result inintensity variations across the collection region 1308. Furthermore,light from the different emitters may not be homogenously mixed so somefibers may receive different amounts of light of different colors.Variation in the color or intensity of light in different fibers canlead to non-optimal illumination of a scene. For example, variations indelivered light or light intensities may result at the scene andcaptured images.

In one embodiment, an intervening optical element may be placed betweena fiber bundle and the emitters 1302, 1304, 1306 to mix the differentcolors (wavelengths) of light before entry into the fibers or otherwaveguide. Example intervening optical elements include a diffuser,mixing rod, one or more lenses, or other optical components that mix thelight so that a given fiber receive a same amount of each color(wavelength). For example, each fiber in the fiber bundle may have asame color. This mixing may lead to the same color in each fiber butmay, in some embodiments, still result in different total brightnessdelivered to different fibers. In one embodiment, the interveningoptical element may also spread out or even out the light over thecollection region so that each fiber carries the same total amount oflight (e.g., the light may be spread out in a top hat profile). Adiffuser or mixing rod may lead to loss of light.

Although the collection region 1308 is represented as a physicalcomponent in FIG. 13A, the collection region 1308 may simply be a regionwhere light from the emitters 1302, 1304, and 1306 is delivered. In somecases, the collection region 1308 may include an optical component suchas a diffuser, mixing rod, lens, or any other intervening opticalcomponent between the emitters 1302, 1304, 1306 and an output waveguide.

FIG. 13C illustrates an embodiment of a light source 1300 with emitters1302, 1304, 1306 that provide light to the collection region 1308 at thesame or substantially same angle. The light is provided at an anglesubstantially perpendicular to the collection region 1308. The lightsource 1300 includes a plurality of dichroic mirrors including a firstdichroic mirror 1310, a second dichroic mirror 1312, and a thirddichroic mirror 1314. The dichroic mirrors 1310, 1312, 1314 includemirrors that reflect a first wavelength of light but transmit (or aretransparent to) a second wavelength of light. For example, the thirddichroic mirror 1314 may reflect blue laser light provided by the thirdemitter, while being transparent to the red and green light provided bythe first emitter 1302 and the second emitter 1304, respectively. Thesecond dichroic mirror 1312 may be transparent to red light from thefirst emitter 1302, but reflective to green light from the secondemitter 1304. If other colors or wavelengths are included dichroicmirrors may be selected to reflect light corresponding to at least oneemitter and be transparent to other emitters. For example, the thirddichroic mirror 1314 reflect the light form the third emitter 1306 butis to emitters “behind” it, such as the first emitter 1302 and thesecond emitter 1304. In embodiments where tens or hundreds of emittersare present, each dichroic mirror may be reflective to a correspondingemitter and emitters in front of it while being transparent to emittersbehind it. This may allow for tens or hundreds of emitters to emitelectromagnetic energy to the collection region 1308 at a substantiallysame angle.

Because the dichroic mirrors allow other wavelengths to transmit or passthrough, each of the wavelengths may arrive at the collection region1308 from a same angle and/or with the same center or focal point.Providing light from the same angle and/or same focal/center point cansignificantly improve reception and color mixing at the collectionregion 1308. For example, a specific fiber may receive the differentcolors in the same proportions they were transmitted/reflected by theemitters 1302, 1304, 1306 and mirrors 1310, 1312, 1314. Light mixing maybe significantly improved at the collection region compared to theembodiment of FIG. 13B. In one embodiment, any optical componentsdiscussed herein may be used at the collection region 1308 to collectlight prior to providing it to a fiber or fiber bundle.

FIG. 13C illustrates an embodiment of a light source 1300 with emitters1302, 1304, 1306 that also provide light to the collection region 1308at the same or substantially same angle. However, the light incident onthe collection region 1308 is offset from being perpendicular. Angle1316 indicates the angle offset from perpendicular. In one embodiment,the laser emitters 1302, 1304, 1306 may have cross sectional intensityprofiles that are Gaussian. As discussed previously, improveddistribution of light energy between fibers may be accomplished bycreating a more flat or top-hat shaped intensity profile. In oneembodiment, as the angle 1316 is increased, the intensity across thecollection region 1308 approaches a top hat profile. For example, atop-hat profile may be approximated even with a non-flat output beam byincreasing the angle 1316 until the profile is sufficiently flat. Thetop hat profile may also be accomplished using one or more lenses,diffusers, mixing rods, or any other intervening optical componentbetween the emitters 1302, 1304, 1306 and an output waveguide, fiber, orfiber optic bundle.

FIG. 14 is a schematic diagram illustrating a single optical fiber 1402outputting via a diffuser 1404 at an output. In one embodiment, theoptical fiber 1402 has a diameter of 500 microns, a numerical apertureof 0.65, and emits a light cone 1406 of about 70 or 80 degrees without adiffuser 1404. With the diffuser 1404, the light cone 1406 may have anangle of about 110 or 120 degrees. The light cone 1406 may be a majorityof where all light goes and is evenly distributed. The diffuser 1404 mayallow for more even distribution of electromagnetic energy of a sceneobserved by an image sensor.

In one embodiment, the lumen waveguide 210 includes a single plastic orglass optical fiber of about 500 microns. The plastic fiber may be lowcost, but the width may allow the fiber to carry a sufficient amount oflight to a scene, with coupling, diffusion, or other losses. Forexample, smaller fibers may not be able to carry as much light or poweras a larger fiber. The lumen waveguide 210 may include a single or aplurality of optical fibers. The lumen waveguide 210 may receive lightdirectly from the light source or via a jumper waveguide. A diffuser maybe used to broaden the light output 206 for a desired field of view ofthe image sensor 214 or other optical components.

Although three emitters are shown in FIGS. 13A-13C, emitters numberingfrom one into the hundreds or more may be used in some embodiments. Theemitters may have different wavelengths or spectrums of light that theyemit, and which may be used to contiguously cover a desired portion ofthe electromagnetic spectrum (e.g., the visible spectrum as well asinfrared and ultraviolet spectrums). The emitters may be configured toemit visible light such as red light, green light, and blue light, andmay further be configured to emit hyperspectral emissions ofelectromagnetic radiation, fluorescence excitation wavelengths forfluorescing a reagent, and/or laser mapping patterns for calculatingparameters and distances between objects in a scene.

FIG. 15 illustrates a portion of the electromagnetic spectrum 1500divided into twenty different sub-spectrums. The number of sub-spectrumsis illustrative only. In at least one embodiment, the spectrum 1500 maybe divided into hundreds of sub-spectrums, each with a small waveband.The spectrum may extend from the infrared spectrum 1502, through thevisible spectrum 1504, and into the ultraviolet spectrum 1506. Thesub-spectrums each have a waveband 1508 that covers a portion of thespectrum 1500. Each waveband may be defined by an upper wavelength and alower wavelength.

Hyperspectral imaging includes imaging information from across theelectromagnetic spectrum 1500. A hyperspectral pulse of electromagneticradiation may include a plurality of sub-pulses spanning one or moreportions of the electromagnetic spectrum 1500 or the entirety of theelectromagnetic spectrum 1500. A hyperspectral pulse of electromagneticradiation may include a single partition of wavelengths ofelectromagnetic radiation. A resulting hyperspectral exposure frameincludes information sensed by the pixel array subsequent to ahyperspectral pulse of electromagnetic radiation. Therefore, ahyperspectral exposure frame may include data for any suitable partitionof the electromagnetic spectrum 1500 and may include multiple exposureframes for multiple partitions of the electromagnetic spectrum 1500. Inan embodiment, a hyperspectral exposure frame includes multiplehyperspectral exposure frames such that the combined hyperspectralexposure frame comprises data for the entirety of the electromagneticspectrum 1500.

In one embodiment, at least one emitter (such as a laser emitter) isincluded in a light source (such as the light sources 202, 1300) foreach sub-spectrum to provide complete and contiguous coverage of thewhole spectrum 1500. For example, a light source for providing coverageof the illustrated sub-spectrums may include at least 20 differentemitters, at least one for each sub-spectrum. In one embodiment, eachemitter covers a spectrum covering 40 nanometers. For example, oneemitter may emit light within a waveband from 500 nm to 540 nm whileanother emitter may emit light within a waveband from 540 nm to 580 nm.In another embodiment, emitters may cover other sizes of wavebands,depending on the types of emitters available or the imaging needs. Forexample, a plurality of emitters may include a first emitter that coversa waveband from 500 to 540 nm, a second emitter that covers a wavebandfrom 540 nm to 640 nm, and a third emitter that covers a waveband from640 nm to 650 nm. Each emitter may cover a different slice of theelectromagnetic spectrum ranging from far infrared, mid infrared, nearinfrared, visible light, near ultraviolet and/or extreme ultraviolet. Insome cases, a plurality of emitters of the same type or wavelength maybe included to provide sufficient output power for imaging. The numberof emitters needed for a specific waveband may depend on the sensitivityof a monochrome sensor to the waveband and/or the power outputcapability of emitters in that waveband.

The waveband widths and coverage provided by the emitters may beselected to provide any desired combination of spectrums. For example,contiguous coverage of a spectrum using very small waveband widths(e.g., 10 nm or less) may allow for highly selective hyperspectraland/or fluorescence imaging. The waveband widths may allow forselectively emitting the excitation wavelength(s) for one or moreparticular fluorescent reagents. Additionally, the waveband widths mayallow for selectively emitting certain partitions of hyperspectralelectromagnetic radiation for identifying specific structures, chemicalprocesses, tissues, biological processes, and so forth. Because thewavelengths come from emitters which can be selectively activated,extreme flexibility for fluorescing one or more specific fluorescentreagents during an examination can be achieved. Additionally, extremeflexibility for identifying one or more objects or processes by way ofhyperspectral imaging can be achieved. Thus, much more fluorescenceand/or hyperspectral information may be achieved in less time and withina single examination which would have required multiple examinations,delays because of the administration of dyes or stains, or the like.

FIG. 16 is a schematic diagram illustrating a timing diagram 1600 foremission and readout for generating an image. The solid line representsreadout (peaks 1602) and blanking periods (valleys) for capturing aseries of exposure frames 1604-1614. The series of exposure frames1604-1614 may include a repeating series of exposure frames which may beused for generating laser mapping, hyperspectral, and/or fluorescencedata that may be overlaid on an RGB video stream. In an embodiment, asingle image frame comprises information from multiple exposure frames,wherein one exposure frame includes red image data, another exposureframe includes green image data, and another exposure frame includesblue image data. Additionally, the single image frame may include one ormore of hyperspectral image data, fluorescence image data, and lasermapping data. The multiple exposure frames are combined to produce thesingle image frame. The single image frame is an RGB image withhyperspectral imaging data. The series of exposure frames include afirst exposure frame 1604, a second exposure frame 1606, a thirdexposure frame 1608, a fourth exposure frame 1610, a fifth exposureframe 1612, and an Nth exposure frame 1626.

Additionally, the hyperspectral image data, the fluorescence image data,and the laser mapping data can be used in combination to identifycritical tissues or structures and further to measure the dimensions ofthose critical tissues or structures. For example, the hyperspectralimage data may be provided to a corresponding system to identify certaincritical structures in a body such as a nerve, ureter, blood vessel,cancerous tissue, and so forth. The location and identification of thecritical structures may be received from the corresponding system andmay further be used to generate topology of the critical structuresusing the laser mapping data. For example, a corresponding systemdetermines the location of a cancerous tumor based on hyperspectralimaging data. Because the location of the cancerous tumor is known basedon the hyperspectral imaging data, the topology and distances of thecancerous tumor may then be calculated based on laser mapping data. Thisexample may also apply when a cancerous tumor or other structure isidentified based on fluorescence imaging data.

In one embodiment, each exposure frame is generated based on at leastone pulse of electromagnetic energy. The pulse of electromagnetic energyis reflected and detected by an image sensor and then read out in asubsequent readout (1602). Thus, each blanking period and readoutresults in an exposure frame for a specific spectrum of electromagneticenergy. For example, the first exposure frame 1604 may be generatedbased on a spectrum of a first one or more pulses 1616, a secondexposure frame 1606 may be generated based on a spectrum of a second oneor more pulses 1618, a third exposure frame 1608 may be generated basedon a spectrum of a third one or more pulses 1620, a fourth exposureframe 1610 may be generated based on a spectrum of a fourth one or morepulses 1622, a fifth exposure frame 1612 may be generated based on aspectrum of a fifth one or more pulses 2424, and an Nth exposure frame1626 may be generated based on a spectrum of an Nth one or more pulses1626.

The pulses 1616-1626 may include energy from a single emitter or from acombination of two or more emitters. For example, the spectrum includedin a single readout period or within the plurality of exposure frames1604-1614 may be selected for a desired examination or detection of aspecific tissue or condition. According to one embodiment, one or morepulses may include visible spectrum light for generating an RGB or blackand white image while one or more additional pulses are emitted to sensea spectral response to a hyperspectral wavelength of electromagneticradiation. For example, pulse 1616 may include red light, pulse 1618 mayinclude blue light, and pulse 1620 may include green light while theremaining pulses 1622-1626 may include wavelengths and spectrums fordetecting a specific tissue type, fluorescing a reagent, and/or mappingthe topology of the scene. As a further example, pulses for a singlereadout period include a spectrum generated from multiple differentemitters (e.g., different slices of the electromagnetic spectrum) thatcan be used to detect a specific tissue type. For example, if thecombination of wavelengths results in a pixel having a value exceedingor falling below a threshold, that pixel may be classified ascorresponding to a specific type of tissue. Each frame may be used tofurther narrow the type of tissue that is present at that pixel (e.g.,and each pixel in the image) to provide a very specific classificationof the tissue and/or a state of the tissue (diseased/healthy) based on aspectral response of the tissue and/or whether a fluorescent reagent ispresent at the tissue.

The plurality of frames 1604-1614 is shown having varying lengths inreadout periods and pulses having different lengths or intensities. Theblanking period, pulse length or intensity, or the like may be selectedbased on the sensitivity of a monochromatic sensor to the specificwavelength, the power output capability of the emitter(s), and/or thecarrying capacity of the waveguide.

In one embodiment, dual image sensors may be used to obtainthree-dimensional images or video feeds. A three-dimensional examinationmay allow for improved understanding of a three-dimensional structure ofthe examined region as well as a mapping of the different tissue ormaterial types within the region.

In an example implementation, a fluorescent reagent is provided to apatient, and the fluorescent reagent is configured to adhere tocancerous cells. The fluorescent reagent is known to fluoresce whenradiated with a specific partition of electromagnetic radiation. Therelaxation wavelength of the fluorescent reagent is also known. In theexample implementation, the patient is imaged with an endoscopic imagingsystem as discussed herein. The endoscopic imaging system pulsespartitions of red, green, and blue wavelengths of light to generate anRGB video stream of the interior of the patient's body. Additionally,the endoscopic imaging system pulses the excitation wavelength ofelectromagnetic radiation for the fluorescent reagent that wasadministered to the patient. In the example, the patient has cancerouscells and the fluorescent reagent has adhered to the cancerous cells.When the endoscopic imaging system pulses the excitation wavelength forthe fluorescent reagent, the fluorescent reagent will fluoresce and emita relaxation wavelength. If the cancerous cells are present in the scenebeing imaged by the endoscopic imaging system, then the fluorescentreagent will also be present in the scene and will emit its relaxationwavelength after fluorescing due to the emission of the excitationwavelength. The endoscopic imaging system senses the relaxationwavelength of the fluorescent reagent and thereby senses the presence ofthe fluorescent reagent in the scene. Because the fluorescent reagent isknown to adhere to cancerous cells, the presence of the fluorescentreagent further indicates the presence of cancerous cells within thescene. The endoscopic imaging system thereby identifies the location ofcancerous cells within the scene. The endoscopic imaging system mayfurther emit a laser mapping pulsing scheme for generating a topology ofthe scene and calculating dimensions for objects within the scene. Thelocation of the cancerous cells (as identified by the fluorescenceimaging data) may be combined with the topology and dimensionsinformation calculated based on the laser mapping data. Therefore, theprecise location, size, dimensions, and topology of the cancerous cellsmay be identified. This information may be provided to a medicalpractitioner to aid in excising the cancerous cells. Additionally, thisinformation may be provided to a robotic surgical system to enable thesurgical system to excise the cancerous cells.

In a further example implementation, a patient is imaged with anendoscopic imaging system to identify quantitative diagnosticinformation about the patient's tissue pathology. In the example, thepatient is suspected or known to suffer from a disease that can betracked with hyperspectral imaging to observe the progression of thedisease in the patient's tissue. The endoscopic imaging system pulsespartitions of red, green, and blue wavelengths of light to generate anRGB video stream of the interior of the patient's body. Additionally,the endoscopic imaging system pulses one or more hyperspectralwavelengths of light that permit the system to “see through” sometissues and generate imaging of the tissue that is affected by thedisease. The endoscopic imaging system senses the reflectedhyperspectral electromagnetic radiation to generate hyperspectralimaging data of the diseased tissue, and thereby identifies the locationof the diseased tissue within the patient's body. The endoscopic imagingsystem may further emit a laser mapping pulsing scheme for generating atopology of the scene and calculating dimensions of objects within thescene. The location of the diseased tissue (as identified by thehyperspectral imaging data) may be combined with the topology anddimensions information that is calculated with the laser mapping data.Therefore, the precise location, size, dimensions, and topology of thediseased tissue can be identified. This information may be provided to amedical practitioner to aid in excising, imaging, or studying thediseased tissue. Additionally, this information may be provided to arobotic surgical system to enable the surgical system to excise thediseased tissue.

FIG. 17 is a schematic diagram of an imaging system 1700 having a singlecut filter. The system 1700 includes an endoscope 1706 or other suitableimaging device having a light source 1708 for use in a light deficientenvironment. The endoscope 1706 includes an image sensor 1704 and afilter 1702 for filtering out unwanted wavelengths of light or otherelectromagnetic radiation before reaching the image sensor 1704. Thelight source 1708 transmits light that may illuminate the surface 1712in a light deficient environment such as a body cavity. The light 1710is reflected off the surface 1712 and passes through the filter 1702before hitting the image sensor 1704.

The filter 1702 may be used in an implementation where a fluorescentreagent or dye has been administered. In such an embodiment, the lightsource 1708 emits the excitation wavelength for fluorescing thefluorescent reagent or dye. Commonly, the relaxation wavelength emittedby the fluorescent reagent or dye will be of a different wavelength thanthe excitation wavelength. The filter 1702 may be selected to filter outthe excitation wavelength and permit only the relaxation wavelength topass through the filter and be sensed by the image sensor 1704.

In one embodiment, the filter 1702 is configured to filter out anexcitation wavelength of electromagnetic radiation that causes a reagentor dye to fluoresce such that only the expected relaxation wavelength ofthe fluoresced reagent or dye is permitted to pass through the filter1702 and reach the image sensor 1704. In an embodiment, the filter 1702filters out at least a fluorescent reagent excitation wavelength between770 nm and 790 nm. In an embodiment, the filter 1702 filters out atleast a fluorescent reagent excitation wavelength between 795 nm and 815nm. In an embodiment, the filter 1702 filters out at least a fluorescentreagent excitation wavelength between 770 nm and 790 nm and between 795nm and 815 nm. In these embodiments, the filter 1702 filters out theexcitation wavelength of the reagent and permits only the relaxationwavelength of the fluoresced reagent to be read by the image sensor1704. The image sensor 1704 may be a wavelength-agnostic image sensorand the filter 1702 may be configured to permit the image sensor 1704 toonly receive the relaxation wavelength of the fluoresced reagent and notreceive the emitted excitation wavelength for the reagent. The datadetermined by the image sensor 1704 may then indicate a presence of acritical body structure, tissue, biological process, or chemical processas determined by a location of the reagent or dye.

The filter 1702 may further be used in an implementation where afluorescent reagent or dye has not been administered. The filter 1702may be selected to permit wavelengths corresponding to a desiredspectral response to pass through and be read by the image sensor 1704.The image sensor 1704 may be a monochromatic image sensor such thatpixels of the captured image that exceed a threshold or fall below athreshold may be characterized as corresponding to a certain spectralresponse or fluorescence emission. The spectral response or fluorescenceemission, as determined by the pixels captured by the image sensor 1704,may indicate the presence of a certain body tissue or structure, acertain condition, a certain chemical process, and so forth.

FIG. 18 is a schematic diagram of an imaging system 1800 having multiplecut filters. The system 1800 includes an endoscope 1806 or othersuitable imaging device having a light source 1808 for use in a lightdeficient environment. The endoscope 1806 includes an image sensor 1804and two filters 1802 a, 1802 b. It should be appreciated that inalternative embodiments, the system 1800 may include any number offilters, and the number of filters and the type of filters may beselected for a certain purpose e.g., for gathering imaging informationof a particular body tissue, body condition, chemical process, and soforth. The filters 1802 a, 1802 b are configured for preventing unwantedwavelengths of light or other electromagnetic radiation from beingsensed by the image sensor 1804. The filters 1802 a, 1802 b may beconfigured to filter out unwanted wavelengths from white light or otherelectromagnetic radiation that may be emitted by the light source 1808.

Further to the disclosure with respect to FIG. 17, the filters 1802 a,1802 b may be used in an implementation where a fluorescent reagent ordye has been administered. The filters 1802 a, 1802 b may be configuredfor blocking an emitted excitation wavelength for the reagent or dye andpermitting the image sensor 1804 to only read the relaxation wavelengthof the reagent or dye. Further, the filters 1802 a, 1802 b may be usedin an implementation where a fluorescent reagent or dye has not beenadministered. In such an implementation, the filters 1802 a, 1802 b maybe selected to permit wavelengths corresponding to a desired spectralresponse to pass through and be read by the image sensor 1804.

The multiple filters 1802 a, 1802 b may each be configured for filteringout a different range of wavelengths of the electromagnetic spectrum.For example, one filter may be configured for filtering out wavelengthslonger than a desired wavelength range and the additional filter may beconfigured for filtering out wavelengths shorter than the desiredwavelength range. The combination of the two or more filters may resultin only a certain wavelength or band of wavelengths being read by theimage sensor 1804.

In an embodiment, the filters 1802 a, 1802 b are customized such thatelectromagnetic radiation between 513 nm and 545 nm contacts the imagesensor 1804. In an embodiment, the filters 1802 a, 1802 b are customizedsuch that electromagnetic radiation between 565 nm and 585 nm contactsthe image sensor 1804. In an embodiment, the filters 1802 a, 1802 b arecustomized such that electromagnetic radiation between 900 nm and 1000nm contacts the image sensor 1804. In an embodiment, the filters 1802 a,1802 b are customized such that electromagnetic radiation between 417 nmand 475 nm contacts the image sensor 1804. In an embodiment, the filters1802 a, 1802 b are customized such that electromagnetic radiationbetween 520 nm and 545 nm contacts the image sensor 1804. In anembodiment, the filters 1802 a, 1802 b are customized such thatelectromagnetic radiation between 617 nm and 645 nm contacts the imagesensor 1804. In an embodiment, the filters 1802 a, 1802 b are customizedsuch that electromagnetic radiation between 760 nm and 795 nm contactsthe image sensor 1804. In an embodiment, the filters 1802 a, 1802 b arecustomized such that electromagnetic radiation between 795 nm and 815 nmcontacts the image sensor 1804. In an embodiment, the filters 1802 a,1802 b are customized such that electromagnetic radiation between 370 nmand 420 nm contacts the image sensor 1804. In an embodiment, the filters1802 a, 1802 b are customized such that electromagnetic radiationbetween 600 nm and 670 nm contacts the image sensor 1804. In anembodiment, the filters 1802 a, 1802 b are configured for permittingonly a certain fluorescence relaxation emission to pass through thefilters 1802 a, 1802 b and contact the image sensor 1804. In anembodiment, a first filter blocks electromagnetic radiation having awavelength from about 770 nm to about 790 nm, and a second filter blockselectromagnetic radiation having a wavelength from about 795 nm to about815 nm.

In an embodiment, the system 1800 includes multiple image sensors 1804and may particularly include two image sensors for use in generating athree-dimensional image. The image sensor(s) 1804 may becolor/wavelength agnostic and configured for reading any wavelength ofelectromagnetic radiation that is reflected off the surface 1812. In anembodiment, the image sensors 1804 are each color dependent orwavelength dependent and configured for reading electromagneticradiation of a particular wavelength that is reflected off the surface1812 and back to the image sensors 1804. Alternatively, the image sensor1804 may include a single image sensor with a plurality of differentpixel sensors configured for reading different wavelengths or colors oflight, such as a Bayer filter color filter array. Alternatively, theimage sensor 1804 may include one or more color agnostic image sensorsthat may be configured for reading different wavelengths ofelectromagnetic radiation according to a pulsing schedule such as thoseillustrated in FIGS. 5-7E, for example.

FIGS. 19A and 19B illustrate a perspective view and a side view,respectively, of an implementation of an imaging sensor 1900 having aplurality of pixel arrays for producing a three-dimensional image. Thethree-dimensional image sensor may be built on a plurality of substratesand may comprise the plurality of pixel arrays and other associatedcircuitry, wherein a plurality of pixel columns 1904 a forming the firstpixel array and a plurality of pixel columns 1904 b forming a secondpixel array are located on respective substrates 1902 a and 1902 b,respectively, and a plurality of circuit columns 1908 a and 1908 b arelocated on a separate substrate 1906. Also illustrated are theelectrical connections and communications between columns of pixels toassociated or corresponding column of circuitry.

The plurality of pixel arrays may sense information simultaneously andthe information from the plurality of pixel arrays may be combined togenerate a three-dimensional image. In an embodiment, an endoscopicimaging system includes two or more pixel arrays that can be deployed togenerate three-dimensional imaging. The endoscopic imaging system mayinclude an emitter for emitting pulses of electromagnetic radiationduring a blanking period of the pixel arrays. The pixel arrays may besynced such that the optical black pixels are read (i.e., the blankingperiod occurs) at the same time for the two or more pixel arrays. Theemitter may emit pulses of electromagnetic radiation for charging eachof the two or more pixel arrays. The two or more pixel arrays may readtheir respective charged pixels at the same time such that the readoutperiods for the two or more pixel arrays occur at the same time or atapproximately the same time. In an embodiment, the endoscopic imagingsystem includes multiple emitters that are each individual synced withone or more pixel arrays of a plurality of pixel arrays. Informationfrom a plurality of pixel arrays may be combined to generatethree-dimensional image frames and video streams.

FIGS. 20A and 20B illustrate a perspective view and a side view,respectively, of an implementation of a monolithic sensor 2000 having aplurality of pixel arrays for producing a three-dimensional image inaccordance with the teachings and principles of the disclosure. Such animplementation may be desirable for three-dimensional image capture,wherein the two-pixel arrays 2002 and 2004 may be offset during use. Inanother implementation, a first pixel array 2002 and a second pixelarray 2004 may be dedicated to receiving a predetermined range of wavelengths of electromagnetic radiation, wherein the first pixel array isdedicated to a different range of wavelength electromagnetic radiationthan the second pixel array.

FIGS. 21A and 21B illustrate a perspective view and a side view,respectively, of an implementation of an imaging sensor 2100 built on aplurality of substrates. As illustrated, a plurality of pixel columns2104 forming the pixel array are located on the first substrate 2102 anda plurality of circuit columns 2108 are located on a second substrate2106. Also illustrated in the figure are the electrical connection andcommunication between one column of pixels to its associated orcorresponding column of circuitry. In one implementation, an imagesensor, which might otherwise be manufactured with its pixel array andsupporting circuitry on a single, monolithic substrate/chip, may havethe pixel array separated from all or a majority of the supportingcircuitry. The disclosure may use at least two substrates/chips, whichwill be stacked together using three-dimensional stacking technology.The first 2102 of the two substrates/chips may be processed using animage CMOS process. The first substrate/chip 2102 may be comprisedeither of a pixel array exclusively or a pixel array surrounded bylimited circuitry. The second or subsequent substrate/chip 2106 may beprocessed using any process and does not have to be from an image CMOSprocess. The second substrate/chip 1306 may be, but is not limited to, ahighly dense digital process to integrate a variety and number offunctions in a very limited space or area on the substrate/chip, or amixed-mode or analog process to integrate for example precise analogfunctions, or a RF process to implement wireless capability, or MEMS(Micro-Electro-Mechanical Systems) to integrate MEMS devices. The imageCMOS substrate/chip 2102 may be stacked with the second or subsequentsubstrate/chip 2106 using any three-dimensional technique. The secondsubstrate/chip 2106 may support most, or a majority, of the circuitrythat would have otherwise been implemented in the first image CMOS chip2102 (if implemented on a monolithic substrate/chip) as peripheralcircuits and therefore have increased the overall system area whilekeeping the pixel array size constant and optimized to the fullestextent possible. The electrical connection between the twosubstrates/chips may be done through interconnects, which may be wirebonds, bump and/or TSV (Through Silicon Via).

It will be appreciated that the teachings and principles of thedisclosure may be used in a reusable device platform, a limited usedevice platform, a re-posable use device platform, or a singleuse/disposable device platform without departing from the scope of thedisclosure. It will be appreciated that in a re-usable device platforman end-user is responsible for cleaning and sterilization of the device.In a limited use device platform, the device can be used for somespecified amount of times before becoming inoperable. Typical new deviceis delivered sterile with additional uses requiring the end-user toclean and sterilize before additional uses. In a re-posable use deviceplatform, a third-party may reprocess the device (e.g., cleans, packagesand sterilizes) a single-use device for additional uses at a lower costthan a new unit. In a single use/disposable device platform a device isprovided sterile to the operating room and used only once before beingdisposed of.

EXAMPLES

The following examples pertain to preferred features of furtherembodiments:

Example 1 is a system. The system includes an emitter for emittingpulses of electromagnetic radiation and an image sensor comprising apixel array for sensing reflected electromagnetic radiation, wherein theimage sensor is disposed within a lumen of an endoscope. The systemincludes a rotation sensor for detecting an angle of rotation of thelumen relative to a handpiece of the endoscope. The system includes acontroller in electronic communication with the emitter and the imagesensor. The system is such that at least a portion of the pulses ofelectromagnetic radiation emitted by the emitter compriseselectromagnetic radiation having a wavelength from about 770 nm to about790, and/or from about 795 nm to about 815 nm.

Example 2 is a system as in Example 1, wherein the lumen is rotatableabout an axis of the endoscope and with respect to the handpiece.

Example 3 is a system as in any of Examples 1-2, further comprising: animage signal processing pipeline for performing rotation transformationson exposure frames captured by the image sensor based on the angle ofrotation detected by the rotation sensor; wherein the image signalprocessing pipeline rotates the exposure frames counter to the angle ofrotation to maintain a consistent image horizon of a scene being imagedby the image sensor.

Example 4 is a system as in any of Examples 1-3, wherein the rotationsensor is a rotation-detecting Hall-effect sensor and is located in thehandpiece of the endoscope.

Example 5 is a system as in any of Examples 1-4, further comprising adiametrically-polarized, magnetic annulus, and wherein the rotationsensor generates a voltage that is used to detect an angle of thediametrically-polarized, magnetic annulus.

Example 6 is a system as in any of Examples 1-5, wherein the rotationsensor generates a voltage that is used to detect the angle of rotationof the lumen relative to the handpiece.

Example 7 is a system as in any of Examples 1-6, wherein the rotationsensor is a potentiometer comprising a carbon filament, wherein thecarbon filament is disposed within the lumen of the endoscope.

Example 8 is a system as in any of Examples 1-7, wherein the rotationsensor comprises a light source and a photo diode that rotate relativeto a gradient disc, and wherein the photo diode detects electromagneticenergy emitted by the light source that is reflected off the gradientdisc.

Example 9 is a system as in any of Examples 1-8, further comprising animage signal processing pipeline for performing rotation transformationson exposure frames captured by the image sensor based on the angle ofrotation detected by the rotation sensor, wherein the image rotationtransformation comprises: identifying integer (x,y) coordinates forpixel data in an exposure frame captured by a pixel of the pixel array;applying a rotation kernel to the integer (x,y) coordinates to transformthe integer (x,y) coordinates to real number pixel coordinates;truncating the real number pixel coordinates to integer values; andassigning values to blank pixel data in the exposure frame using valuesof nearby, filled pixel data from the exposure frame.

Example 10 is a system as in any of Examples 1-9, further comprising animage signal processing pipeline for performing rotation transformationson exposure frames captured by the image sensor based on the angle ofrotation detected by the rotation sensor, wherein the image rotationtransformation comprises: identifying integer (x,y) coordinates forpixel data in an exposure frame captured by a pixel of the pixel array;applying an inverse rotation kernel to the integer (x,y) coordinates totransform the integer (x,y) coordinates to real number (x,y)coordinates; and estimating a pixel value at the real number (x,y)coordinates using data from one or more closest integer coordinatelocations; wherein the estimating is performed using one of nearestneighbor substitution, bilinear interpolation, or bicubic interpolation.

Example 11 is a system as in any of Examples 1-10, wherein the imagesensor is configured to generate a plurality of exposure frames, whereineach of the plurality of exposure frames corresponds to a pulse ofelectromagnetic radiation emitted by the emitter.

Example 12 is a system as in any of Examples 1-11, wherein the pixelarray of the image sensor senses reflected electromagnetic radiation togenerate the plurality of exposure frames during a readout period of thepixel array, wherein the readout period is a duration of time whenactive pixels in the pixel array are read.

Example 13 is a system as in any of Examples 1-12, wherein at least aportion of the pulses of electromagnetic radiation emitted by theemitter is a hyperspectral wavelength for eliciting a spectral response,wherein the hyperspectral wavelength comprises one or more of: theelectromagnetic radiation having the wavelength from about 513 nm toabout 545 nm and the electromagnetic radiation having the wavelengthfrom about 900 nm to about 1000 nm; or the electromagnetic radiationhaving the wavelength from about 565 nm to about 585 nm and theelectromagnetic radiation having the wavelength from about 900 nm toabout 1000 nm.

Example 14 is a system as in any of Examples 1-13, wherein the emitteris configured to emit, during a pulse duration, a plurality ofsub-pulses of electromagnetic radiation having a sub-duration shorterthan the pulse duration.

Example 15 is a system as in any of Examples 1-14, wherein one or moreof the pulses of electromagnetic radiation emitted by the emittercomprises electromagnetic radiation emitted at two or more wavelengthssimultaneously as a single pulse or a single sub-pulse.

Example 16 is a system as in any of Examples 1-15, wherein at least aportion of the pulses of electromagnetic radiation emitted by theemitter is a hyperspectral emission that results in a hyperspectralexposure frame created by the image sensor, and wherein the controlleris configured to provide the hyperspectral exposure frame to acorresponding hyperspectral system that determines a location of acritical tissue structure within a scene based on the hyperspectralexposure frame.

Example 17 is a system as in any of Examples 1-16, wherein thehyperspectral emission comprises: the electromagnetic radiation havingthe wavelength from about 513 nm to about 545 nm and the electromagneticradiation having the wavelength from about 900 nm to about 1000 nm; orthe electromagnetic radiation having the wavelength from about 565 nm toabout 585 nm and the electromagnetic radiation having the wavelengthfrom about 900 nm to about 1000 nm.

Example 18 is a system as in any of Examples 1-17, wherein thecontroller is further configured to: receive the location of thecritical tissue structure from the corresponding hyperspectral system;generate an overlay frame comprising the location of the critical tissuestructure; and combine the overlay frame with a color image framedepicting the scene to indicate the location of the critical tissuestructure within the scene.

Example 19 is a system as in any of Examples 1-18, wherein sensing thereflected electromagnetic radiation by the pixel array comprisesgenerating a laser mapping exposure frame by sensing reflectedelectromagnetic radiation resulting from the emitter pulsing the lasermapping pattern, and wherein the controller is further configured to:provide the laser mapping exposure frame to a corresponding lasermapping system that determines a topology of the scene and/or dimensionsof one or more objects within the scene; provide the location of thecritical tissue structure to the corresponding laser mapping system; andreceive a topology and/or dimension of the critical tissue structurefrom the corresponding laser mapping system.

Example 20 is a system as in any of Examples 1-19, wherein the criticalstructure comprises one or more of a nerve, a ureter, a blood vessel, anartery, a blood flow, or a tumor.

Example 21 is a system as in any of Examples 1-20, wherein at least aportion of the pulses of electromagnetic radiation emitted by theemitter is the fluorescence excitation wavelength that results in afluorescence exposure frame created by the image sensor, and wherein thecontroller is configured to provide the fluorescence exposure frame to acorresponding fluorescence system that determines a location of acritical tissue structure within a scene based on the fluorescenceexposure frame.

Example 22 is a system as in any of Examples 1-21, wherein thefluorescence excitation emission comprises one or more of:electromagnetic radiation having a wavelength from about 770 nm to about790 nm; or the electromagnetic radiation having the wavelength fromabout 795 nm to about 815 nm.

Example 23 is a system as in any of Examples 1-22, wherein thecontroller is further configured to: receive the location of thecritical tissue structure from the corresponding fluorescence system;generate an overlay frame comprising the location of the critical tissuestructure; and combine the overlay frame with a color image framedepicting the scene to indicate the location of the critical tissuestructure within the scene.

Example 24 is a system as in any of Examples 1-23, wherein sensing thereflected electromagnetic radiation by the pixel array comprisesgenerating a laser mapping exposure frame by sensing reflectedelectromagnetic radiation resulting from the emitter pulsing the lasermapping pattern, and wherein the controller is further configured to:provide the laser mapping exposure frame to a corresponding lasermapping system that determines a topology of the scene and/or dimensionsof one or more objects within the scene; provide the location of thecritical tissue structure to the corresponding laser mapping system; andreceive a topology and/or dimension of the critical tissue structurefrom the corresponding laser mapping system.

Example 25 is a system as in any of Examples 1-24, wherein the criticalstructure comprises one or more of a nerve, a ureter, a blood vessel, anartery, a blood flow, or a tumor.

Example 26 is a system as in any of Examples 1-25, wherein thecontroller is configured to synchronize timing of the pulses ofelectromagnetic radiation during a blanking period of the image sensor,wherein the blanking period corresponds to a time between a readout of alast row of active pixels in the pixel array and a beginning of a nextsubsequent readout of active pixels in the pixel array.

Example 27 is a system as in any of Examples 1-26, wherein two or morepulses of electromagnetic radiation emitted by the emitter result in twoor more instances of reflected electromagnetic radiation that are sensedby the pixel array to generate two or more exposure frames that arecombined to form an image frame.

Example 28 is a system as in any of Examples 1-27, wherein the imagesensor comprises a first image sensor and a second image sensor suchthat the image sensor can generate a three-dimensional image.

Example 29 is a system as in any of Examples 1-28, wherein the emitteris configured to emit a sequence of pulses of electromagnetic radiationrepeatedly sufficient for generating a video stream comprising aplurality of image frames, wherein each image frame in the video streamcomprises data from a plurality of exposure frames, and wherein each ofthe exposure frames corresponds to a pulse of electromagnetic radiation.

Example 30 is a system as in any of Examples 1-29, wherein the pulses ofelectromagnetic radiation are emitted in a pattern of varyingwavelengths of electromagnetic radiation, and wherein the emitterrepeats the pattern of varying wavelengths of electromagnetic radiation.

Example 31 is a system as in any of Examples 1-30, wherein at least aportion of the pulses of electromagnetic radiation comprise a redwavelength, a green wavelength, a blue wavelength, and a hyperspectralwavelength such that reflected electromagnetic radiation sensed by thepixel array corresponding to each of the red wavelength, the greenwavelength, the blue wavelength, and the hyperspectral wavelength can beprocessed to generate a Red-Green-Blue (RGB) image frame comprising anoverlay of hyperspectral imaging data, wherein the hyperspectralwavelength of electromagnetic radiation comprises: the electromagneticradiation having the wavelength from about 513 nm to about 545 nm andthe electromagnetic radiation having the wavelength from about 900 nm toabout 1000 nm; or the electromagnetic radiation having the wavelengthfrom about 565 nm to about 585 nm and the electromagnetic radiationhaving the wavelength from about 900 nm to about 1000 nm.

Example 32 is a system as in any of Examples 1-31, wherein at least aportion of the pulses of electromagnetic radiation comprise a luminanceemission, a red chrominance emission, a blue chrominance emission, and ahyperspectral emission such that reflected electromagnetic radiationsensed by the pixel array corresponding to each of the luminanceemission, the red chrominance emission, the blue chrominance emission,and the hyperspectral emission can be processed to generate a YCbCrimage frame comprising an overlay of hyperspectral imaging data, whereinthe hyperspectral emission of electromagnetic radiation comprises: theelectromagnetic radiation having the wavelength from about 513 nm toabout 545 nm and the electromagnetic radiation having the wavelengthfrom about 900 nm to about 1000 nm; or the electromagnetic radiationhaving the wavelength from about 565 nm to about 585 nm and theelectromagnetic radiation having the wavelength from about 900 nm toabout 1000 nm.

Example 33 is a system as in any of Examples 1-32, wherein the lumen ofthe endoscope is rotatable about an axis of the endoscope and withrespect to the handpiece of the endoscope.

Example 34 is a system as in any of Examples 1-33, wherein the endoscopecomprises a proximal portion and a distal portion, wherein the lumen andthe image sensor are disposed at the distal portion and the handpiece isdisposed at the proximal portion.

Example 35 is a system as in any of Examples 1-34, wherein thecontroller comprises an image signal processing pipeline for performingrotation transformations on exposure frames captured by the image sensorbased on the angle of rotation detected by the rotation sensor, whereinthe image signal processing pipeline is configured to rotate theexposure frames counter to the angle of rotation detected by therotation sensor to maintain a constant image horizon.

Example 36 is a system as in any of Examples 1-35, wherein anorientation of rotated exposure frames is rotationally different than anorientation of the lumen relative to the handpiece.

Example 37 is a system as in any of Examples 1-36, wherein the pixelarray is a two-dimensional array of independent pixels each capable ofdetecting any wavelength of electromagnetic radiation.

Example 38 is a system as in any of Examples 1-37, wherein assigning thevalues to the blank pixel data in the exposure frames is performed bybilinear interpolation.

Example 39 is a system as in any of Examples 1-38, wherein assigning thevalues to the blank pixel data in the exposure frames is performed bybicubic interpolation.

Example 40 is a system as in any of Examples 1-39, wherein assigning thevalues to the blank pixel data in the exposure frames is performed bynearest neighbor substitution.

Example 41 is a system as in any of Examples 1-40, further comprising afilter that filters electromagnetic radiation having a wavelength fromabout 770 nm to about 790 nm.

Example 42 is a system as in any of Examples 1-41, further comprising afilter that filters electromagnetic radiation having a wavelength fromabout 795 nm to about 815 nm.

Example 43 is a system as in any of Examples 1-42, wherein at least aportion of the pulses of electromagnetic radiation emitted by theemitter is a fluorescence excitation wavelength for fluorescing areagent, wherein the fluorescence excitation wavelength comprises one ormore of: the electromagnetic radiation having the wavelength from about770 nm to about 790 nm; or the electromagnetic radiation having thewavelength from about 795 nm to about 815 nm.

Example 44 is a system as in any of Examples 1-43, wherein at least aportion of the pulses of electromagnetic radiation comprise a redwavelength, a green wavelength, a blue wavelength, and a fluorescenceexcitation wavelength such that reflected electromagnetic radiationsensed by the pixel array corresponding to each of the red wavelength,the green wavelength, the blue wavelength, and the fluorescenceexcitation wavelength can be processed to generate a Red-Green-Blue(RGB) image frame comprising an overlay of fluorescence imaging data,wherein the fluorescence wavelength of electromagnetic radiationcomprises: electromagnetic radiation having the wavelength from about770 nm to about 790 nm and/or electromagnetic radiation having thewavelength from about 795 nm to about 815 nm.

Example 45 is a system as in any of Examples 1-44, wherein at least aportion of the pulses of electromagnetic radiation comprise a luminanceemission, a red chrominance emission, a blue chrominance emission, and afluorescence excitation emission such that reflected electromagneticradiation sensed by the pixel array corresponding to each of theluminance emission, the red chrominance emission, the blue chrominanceemission, and the fluorescence excitation emission can be processed togenerate a YCbCr image frame comprising an overlay of fluorescenceimaging data, wherein the fluorescence wavelength of electromagneticradiation comprises: electromagnetic radiation having the wavelengthfrom about 770 nm to about 790 nm and/or electromagnetic radiationhaving the wavelength from about 795 nm to about 815 nm.

It will be appreciated that various features disclosed herein providesignificant advantages and advancements in the art. The following claimsare exemplary of some of those features.

In the foregoing Detailed Description of the Disclosure, variousfeatures of the disclosure are grouped together in a single embodimentfor the purpose of streamlining the disclosure. This method ofdisclosure is not to be interpreted as reflecting an intention that theclaimed disclosure requires more features than are expressly recited ineach claim. Rather, inventive aspects lie in less than all features of asingle foregoing disclosed embodiment.

It is to be understood that any features of the above-describedarrangements, examples, and embodiments may be combined in a singleembodiment comprising a combination of features taken from any of thedisclosed arrangements, examples, and embodiments.

It is to be understood that the above-described arrangements are onlyillustrative of the application of the principles of the disclosure.Numerous modifications and alternative arrangements may be devised bythose skilled in the art without departing from the spirit and scope ofthe disclosure and the appended claims are intended to cover suchmodifications and arrangements.

Thus, while the disclosure has been shown in the drawings and describedabove with particularity and detail, it will be apparent to those ofordinary skill in the art that numerous modifications, including, butnot limited to, variations in size, materials, shape, form, function andmanner of operation, assembly and use may be made without departing fromthe principles and concepts set forth herein.

Further, where appropriate, functions described herein can be performedin one or more of: hardware, software, firmware, digital components, oranalog components. For example, one or more application specificintegrated circuits (ASICs) or field programmable gate arrays (FPGAs)can be programmed to carry out one or more of the systems and proceduresdescribed herein. Certain terms are used throughout the followingdescription and claims to refer to particular system components. As oneskilled in the art will appreciate, components may be referred to bydifferent names. This document does not intend to distinguish betweencomponents that differ in name, but not function.

The foregoing description has been presented for the purposes ofillustration and description. It is not intended to be exhaustive or tolimit the disclosure to the precise form disclosed. Many modificationsand variations are possible in light of the above teaching. Further, itshould be noted that any or all the aforementioned alternateimplementations may be used in any combination desired to formadditional hybrid implementations of the disclosure.

Further, although specific implementations of the disclosure have beendescribed and illustrated, the disclosure is not to be limited to thespecific forms or arrangements of parts so described and illustrated.The scope of the disclosure is to be defined by the claims appendedhereto, any future claims submitted here and in different applications,and their equivalents.

What is claimed is:
 1. A system for endoscopic imaging, the systemcomprising: an emitter for emitting pulses of electromagnetic radiation;an image sensor comprising a pixel array for sensing reflectedelectromagnetic radiation, wherein the image sensor is disposed within alumen of an endoscope; a rotation sensor for detecting an angle ofrotation of the lumen relative to a handpiece of the endoscope; and acontroller in electronic communication with the emitter and the imagesensor; wherein at least a portion of the pulses of electromagneticradiation emitted by the emitter comprises one or more of:electromagnetic radiation having a wavelength from about 770 nm to about790 nm; or electromagnetic radiation having a wavelength from about 795nm to about 815 nm.
 2. The system of claim 1, wherein the lumen isrotatable about an axis of the endoscope and with respect to thehandpiece.
 3. The system of claim 1, further comprising: an image signalprocessing pipeline for performing rotation transformations on exposureframes captured by the image sensor based on the angle of rotationdetected by the rotation sensor; wherein the image signal processingpipeline rotates the exposure frames counter to the angle of rotation tomaintain a consistent image horizon of a scene being imaged by the imagesensor.
 4. The system of claim 1, wherein the rotation sensor is arotation-detecting Hall-effect sensor and is located in the handpiece ofthe endoscope.
 5. The system of claim 4, further comprising adiametrically-polarized, magnetic annulus, and wherein the rotationsensor generates a voltage that is used to detect an angle of thediametrically-polarized, magnetic annulus.
 6. The system of claim 1,wherein the rotation sensor generates a voltage that is used to detectthe angle of rotation of the lumen relative to the handpiece.
 7. Thesystem of claim 1, wherein the rotation sensor is a potentiometercomprising a carbon filament, wherein the carbon filament is disposedwithin the lumen of the endoscope.
 8. The system of claim 1, wherein therotation sensor comprises a light source and a photo diode that rotaterelative to a gradient disc, and wherein the photo diode detectselectromagnetic energy emitted by the light source that is reflected offthe gradient disc.
 9. The system of claim 1, further comprising an imagesignal processing pipeline for performing rotation transformations onexposure frames captured by the image sensor based on the angle ofrotation detected by the rotation sensor, wherein calculating the imagerotation transformation comprises: identifying integer (x,y) coordinatesfor pixel data in an exposure frame captured by a pixel of the pixelarray; applying a rotation kernel to the integer (x,y) coordinates totransform the integer (x,y) coordinates to real number pixelcoordinates; truncating the real number pixel coordinates to integervalues; and assigning values to blank pixel data in the exposure frameusing values of nearby, filled pixel data from the exposure frame. 10.The system of claim 1, further comprising an image signal processingpipeline for performing rotation transformations on exposure framescaptured by the image sensor based on the angle of rotation detected bythe rotation sensor, wherein calculating the image rotationtransformation comprises: identifying integer (x,y) coordinates forpixel data in an exposure frame captured by a pixel of the pixel array;applying an inverse rotation kernel to the integer (x,y) coordinates totransform the integer (x,y) coordinates to real number (x,y)coordinates; and estimating a pixel value at the real number (x,y)coordinates using data from one or more closest integer coordinatelocations; wherein the estimating is performed using one of nearestneighbor substitution, bilinear interpolation, or bicubic interpolation.11. The system of claim 1, wherein the image sensor is configured togenerate a plurality of exposure frames, wherein each of the pluralityof exposure frames corresponds to a pulse of electromagnetic radiationemitted by the emitter.
 12. The system of claim 11, wherein the pixelarray of the image sensor senses reflected electromagnetic radiation togenerate the plurality of exposure frames during a readout period of thepixel array, wherein the readout period is a duration of time whenactive pixels in the pixel array are read.
 13. The system of claim 1,wherein at least a portion of the pulses of electromagnetic radiationemitted by the emitter is a fluorescence excitation wavelength forfluorescing a reagent, wherein the fluorescence excitation wavelengthcomprises one or more of: the electromagnetic radiation having thewavelength from about 770 nm to about 790 nm; or the electromagneticradiation having the wavelength from about 795 nm to about 815 nm. 14.The system of claim 1, wherein the emitter is configured to emit, duringa pulse duration, a plurality of sub-pulses of electromagnetic radiationhaving a sub-duration shorter than the pulse duration.
 15. The system ofclaim 1, wherein one or more of the pulses of electromagnetic radiationemitted by the emitter comprises electromagnetic radiation emitted attwo or more wavelengths simultaneously as a single pulse or a singlesub-pulse.
 16. The system of claim 1, wherein at least a portion of thepulses of electromagnetic radiation emitted by the emitter is afluorescence excitation emission that results in a fluorescence exposureframe created by the image sensor, and wherein the controller isconfigured to provide the fluorescence exposure frame to a correspondingsystem that determines a location of a critical tissue structure withina scene based on the fluorescence exposure frame.
 17. The system ofclaim 16, wherein the fluorescence excitation emission comprises eachof: the electromagnetic radiation having the wavelength from about 770nm to about 790 nm; and the electromagnetic radiation having thewavelength from about 795 nm to about 815 nm.
 18. The system of claim17, wherein the controller is further configured to: receive thelocation of the critical tissue structure from the corresponding system;generate an overlay frame comprising the location of the critical tissuestructure; and combine the overlay frame with a color image framedepicting the scene to indicate the location of the critical tissuestructure within the scene.
 19. The system of claim 18, wherein thecritical structure comprises one or more of a nerve, a ureter, a bloodvessel, an artery, a blood flow, or a tumor.
 20. The system of claim 1,wherein the controller is configured to synchronize timing of the pulsesof electromagnetic radiation during a blanking period of the imagesensor, wherein the blanking period corresponds to a time between areadout of a last row of active pixels in the pixel array and abeginning of a next subsequent readout of active pixels in the pixelarray.
 21. The system of claim 1, wherein two or more pulses ofelectromagnetic radiation emitted by the emitter result in two or moreinstances of reflected electromagnetic radiation that are sensed by thepixel array to generate two or more exposure frames that are combined toform an image frame.
 22. The system of claim 1, wherein the image sensorcomprises a first image sensor and a second image sensor such that theimage sensor can generate a three-dimensional image.
 23. The system ofclaim 1, wherein the emitter is configured to emit a sequence of pulsesof electromagnetic radiation repeatedly sufficient for generating avideo stream comprising a plurality of image frames, wherein each imageframe in the video stream comprises data from a plurality of exposureframes, and wherein each of the exposure frames corresponds to a pulseof electromagnetic radiation.
 24. The system of claim 1, wherein thepulses of electromagnetic radiation are emitted in a pattern of varyingwavelengths of electromagnetic radiation, and wherein the emitterrepeats the pattern of varying wavelengths of electromagnetic radiation.25. The system of claim 1, wherein at least a portion of the pulses ofelectromagnetic radiation comprise a red wavelength, a green wavelength,a blue wavelength, and a fluorescence excitation wavelength such thatreflected electromagnetic radiation sensed by the pixel arraycorresponding to each of the red wavelength, the green wavelength, theblue wavelength, and the fluorescence excitation wavelength can beprocessed to generate a Red-Green-Blue (RGB) image frame comprising anoverlay of fluorescence imaging data, wherein the fluorescenceexcitation wavelength of electromagnetic radiation comprises: theelectromagnetic radiation having the wavelength from about 770 nm toabout 790 nm; or the electromagnetic radiation having the wavelengthfrom about 795 nm to about 815 nm.
 26. The system of claim 1, wherein atleast a portion of the pulses of electromagnetic radiation comprise aluminance emission, a red chrominance emission, a blue chrominanceemission, and a fluorescence excitation emission such that reflectedelectromagnetic radiation sensed by the pixel array corresponding toeach of the luminance emission, the red chrominance emission, the bluechrominance emission, and the fluorescence excitation emission can beprocessed to generate a YCbCr image frame comprising an overlay offluorescence imaging data, wherein the fluorescence excitation emissionof electromagnetic radiation comprises: the electromagnetic radiationhaving the wavelength from about 770 nm to about 790 nm; or theelectromagnetic radiation having the wavelength from about 795 nm toabout 815 nm.
 27. The system of claim 1, further comprising a filterthat filters electromagnetic radiation having a wavelength from about770 nm to about 790 nm.
 28. The system of claim 1, further comprising afilter that filters electromagnetic radiation having a wavelength fromabout 795 nm to about 815 nm.